PART I
_Growth, Manufacture and Distribution_
WHAT SUGAR IS
Among the many varieties of sugar the most important are the sucroses and the glucoses. They form a natural group of substances, chiefly of vegetable origin. Chemically considered, all sugars are carbohydrates, that is to say, bodies composed of three elements: carbon, hydrogen and oxygen. Sucrose contains twelve atoms of carbon, twenty-two atoms of hydrogen and eleven atoms of oxygen.
Apart from sucrose, which is usually cane and beet sugar, the variety most generally met with is dextrose—one of the glucoses. It possesses less sweetness than sucrose and differs from the latter in chemical composition. As an example: dextrose is found in the raisin in small grains. It also occurs in other fruits and is the result of the inversion of sucrose.
Glucose enters largely into the manufacture of candy, being particularly necessary in the preparation of soft filling for creams, as a certain amount of it added to cane-sugar syrup prevents crystallization.
Sucrose is derived from sugar cane, maple sap, sorghum and the sugar beet. It is a solid, crystallizing in the form of monoclinic prisms, generally with hemihedral faces, which are colorless, transparent, have a sweet taste, a specific gravity of 1.6 and a melting point of about 320 degrees Fahrenheit. It is soluble in about one-half its weight in cold water, and in boiling water in almost all proportions. It is practically insoluble in alcohol, turpentine, ether, chloroform and similar fluids.
The crop of 1914-15 showed a world’s production of 18,409,016 long tons of sugar, and in the chapters relating to the history of sugar will be found a statement setting forth the amount produced by each country. The total was derived about one-half from cane and one-half from beets, produced as follows:
CANE BEET Total in America 5,017,375 660,236 ” Asia 4,268,618 ” Australia and Polynesia 348,408 ” Africa 523,788 ” Europe 7,376[4] 7,583,215 ---------- --------- 10,165,565 8,243,451
Sugar cane, described in botany as _Saccharum officinarum_, is a giant-stemmed perennial grass that grows from eight to twenty-four feet long. When ripe it produces at the top of its stalk a large feathery plume of flowers of a gray inflorescence called the “tassel,” which is from two to four feet in length.
There are many kinds of cane, all of which are regarded as varieties of one species, although some botanists have raised a few to the rank of distinct species. The cultivated types are distinguished by the color of the internodes, yellow, red, purple or striped, and by other general characteristics.
The stem of the cane is solid, with joints at intervals of three to six inches. In diameter it ranges from one to two and a half inches, and is unbranched, bearing in its upper part numerous long, narrow grass-like leaves, arranged in two rows. The leaves spring from large sheaths around the joints, and have a more or less spreading blade from three to five feet in length and two inches or more in width. The pith, of open cellular structure, contains the sugary juice. The tops, which contain but little sugar, are not crushed, but are used for seed, as the plant germinates from the eyes, or buds, which grow on the stem around the joints. Practically no cultivated cane is propagated from its seed. The roots that remain in the ground after the cane is harvested throw up fresh canes or ratoons for many seasons, after which replanting is necessary. Hawaiian growers do not count on ratoons for more than a few crops, whereas in Cuba this process can be repeated for many years.
As a rule, sugar cane consists of about eighty-eight per cent of juice and twelve per cent of fiber, the juice content varying from time to time, both as regards quality and amount. The quantity of the juice pressed from the cane determines the efficiency of the extraction, while quality is the main factor when the result of subsequent manufacture is under analysis.
It is difficult to arrive at a fair average of the composition of the juice of the cane, as it varies in different countries, on different plantations in the same country, and at different periods in any one year. The following is an approximation:
Water 80.8 per cent Sugar 16.4 ” Invert sugar 1.98 ” Organic non-sugar .54 ” Ash (mineral matter) .28 ”
THE GROWING OF SUGAR CANE
Sugar cane grows almost exclusively in the tropical belt, extending from twenty-two degrees north to twenty-two degrees south latitude, where the three essentials for its successful culture, viz., fertile soil, hot sunshine and plenty of moisture, are present. It flourishes in the islands of the Pacific ocean, particularly in the Hawaiian group, in Cuba, Mexico, Central America, the islands of the East and West Indies, Australia, China, India, along the shores of the China sea and the Indian ocean, and in certain parts of Africa and South America. In the low latitudes of the temperate zone it is grown with only fair success.
Owing to peculiar climatic conditions, sugar cane has been raised in southern Spain for generations, notwithstanding the fact that the provinces in which the sugar cane is grown lie, roughly speaking, between thirty-six degrees and thirty-eight degrees north latitude. The Gulf Stream is no doubt largely responsible for this phenomenon. The quantity of sugar produced in Spain, however, is small, the crop of 1914-15 amounting to less than 8000 tons.
Sugar cane thrives best in a moist, warm climate, with moderate intervals of dry, hot weather, and plenty of water for irrigation. It requires marly soil, free from saline ingredients. As a rule, it is raised on the lowlands, where the temperature is highest and where it is easy to bring water for irrigation. In Hawaii it takes eighteen months to ripen, and “tasseling” occurs about thirty days before it is ready to be cut. In Louisiana and Texas, because of the short seasons, cane is harvested in from nine to ten months from the time of sprouting, and, consequently, before it has attained maturity. In Cuba it is cut in twelve months, whether it is ripe or not.
As the scientific culture and manufacture of sugar is probably further advanced in the Hawaiian islands than in any other part of the world, a description of the industry as carried on there will serve to illustrate the intensive cultivation and scientific methods of the present day.
The Hawaiian islands are situated in the Pacific ocean, in latitude nineteen degrees to twenty-two degrees north and in longitude one hundred and fifty-four degrees to one hundred and sixty-one degrees west, and are free from the destructive hurricanes of the East and West Indies. They are of volcanic formation and, as a rule, their centers are mountainous, in some instances reaching an elevation of nearly fourteen thousand feet. During the ages, torrential rains carried volcanic ash from the mountains toward the sea, near which it was deposited, thus forming alluvial areas of vast richness around the circumference of the islands. Parts of some of the islands are fringed with coral reefs, barriers that retain the washings from the mountains. In these low-lying areas the soil is extraordinarily fertile, and it is on such ground that the most generous crops are raised.
The soft, warm trade winds that blow from the northeast become laden with moisture as they sweep over the ocean; when they strike the cold mountain peaks the moisture condenses immediately into copious rains. The precipitation in some places reaches the astounding total of three hundred inches per annum. The rain water is conserved and, when needed, is carried to the various plantations by immense irrigation ditches.
In this tropical region there is an abundance of sunshine, accompanied by humid heat, exactly the conditions needed. It required only man’s ingenuity to utilize what nature so lavishly provided.
The commercial cultivation of sugar cane in these islands began about 1850, when a few hundred tons of raw sugar were produced, but the methods of husbandry and manufacture were crude. Time and experience worked great changes, until in 1914-15 the crop of raw sugar totaled 646,448 tons of 2000 pounds each.
For many years past the sugar planters have maintained in Honolulu an experimental station that is the marvel of the agricultural world. The bulletins issued by it are recognized as authoritative, and are read with interest in every sugar-producing country.
The most important features of the work carried on at this station are:
1. SOIL ANALYSIS
Skilled chemists examine the soils of the various plantations and, when occasion demands, advise the planter what necessary element is lacking, as well as how to obtain and apply it. A few years ago this branch of the work was considered highly important. Recently, however, the agriculturists have been depending more upon well-defined systems of experimentation. Each plantation has on its own lands plots of ground on which different methods of culture are tried and on which various kinds of fertilizer are used. Experiments are also made to determine the exact amount of water needed for irrigation. Particular attention is paid to seed cane, and a number of types of it are planted in order to obtain seed that will produce stalks that grow rapidly, yield a large tonnage per acre, contain a maximum amount of sugar, and have a high resistant power against disease and insect pests. The success attending this practical experimental work is such that soil analysis is being relegated to second place.
2. ENTOMOLOGY
A staff of trained experts assiduously study the insect life and eagerly watch for harmful, troublesome pests, which in the past have wrought great damage. It is their duty to find the means of eliminating these pests, and this they usually accomplish through the skillful use of insect parasites.
3. PATHOLOGY
The pathologists attached to the station supplement the scientific labors of the chemists and the entomologists by prescribing for any disease that may attack the cane. Plant life is subject to as many ills as the human family, and the work of these specialists in restoring health to ailing cane is of the highest importance.
To fully illustrate the character and scope of their work, a particular instance for each department may be cited:
A certain planter found that the amount of sugar obtained from his cane was decreasing yearly, though he could see no good reason for it. The land looked right; he ploughed deeply, harrowed well, kept the weeds down, gave the cane plenty of water, could find no reason to complain of climatic conditions, but still did not get satisfactory results. Finally the head of the experimental station was consulted and an agricultural chemist was sent to the plantation. This chemist, after careful investigation, took samples of the soil from various parts of the land; these were analyzed and the source of the trouble was found to be the lack of potash. Just here it may be explained that when the same crop is taken from the land many years in succession, without adequate fertilization, some of the essential properties of the soil become exhausted. Speaking generally, these are lime, soda, potash, phosphates and nitrogen. In this particular instance, as has been said, the land had been gradually drained of its potash. The experimental station recommended the planter to scatter a certain fertilizer over his fields. This advice was followed and the next crop showed remarkable improvement, the yield of cane and sugar per acre being greater than ever before.
At one time the sugar industry of the Hawaiian islands was threatened with annihilation by a little insect called the “leaf-hopper.” The harm done by this pest was so enormous that one plantation having an average yearly crop of 19,000 tons was so severely affected that the yield dropped from 19,000 to 12,000, and then to 3000 tons in three successive crops. All the plantations on the islands suffered to a greater or lesser extent, and the entire sugar industry of Hawaii was jeopardized.
The hoppers punctured the stalks and leaves of the young cane, and in the holes thus formed laid their eggs by thousands. When the young hoppers hatched out, they fed on the juices in the stalk and in the leaves, thus destroying the leaves and depriving the cane of its protection and principal means of absorbing nourishment from the air.
As soon as the leaf-hopper by its ravages made itself known in the islands, the entomologists were consulted, and they were confronted with the task of studying the life and habits of the hopper for the purpose of finding, if possible, some other insects that would attack and exterminate it. It is well known to entomologists that every insect pest has natural enemies; the vital question in this case was—what were the natural enemies of the leaf-hopper and where were they to be found? Obviously, too, the problem was to discover insectivorous enemies that would not themselves attack the cane after they had destroyed the hopper.
After careful investigation it was concluded that the leaf-hopper had been introduced in Hawaii in new varieties of seed cane imported from Australia, and, as the hopper was not doing material damage on the plantations in Australia, the inference was that it must be controlled there by its natural enemy. The chief of the Department of Entomology was sent to London. There in the archives of the British Museum he found a full description of the leaf-hopper and that its native habitat was Queensland, Australia. On his return to Hawaii, entomologists were sent to Australia and the search for the enemy of the hopper began.
For weeks the entomologists virtually lived in the cane fields, undergoing extreme privations, but at last their faithfulness was crowned with success. Several species of parasites that kept the Queensland leaf-hopper in check were discovered, and later on more were found in the islands of Fiji. These tiny creatures as a rule were invisible to the naked eye and could only be seen with the aid of a powerful magnifying glass. All of these insects were parasites either of the leaf-hopper or its eggs. Two of them were particularly efficacious. One, quicker in movement than the hopper, caught it unawares and attached itself to the hopper’s body much in the same way that a mosquito does to a human being. After catching it, the parasite would sting the hopper and lay an egg in its body. In a few days a young parasite was hatched from the egg, and so ravenous was this young insect that it devoured the hopper in a short time and then sought a fresh victim in which to lay its eggs.
The other insect was even more effective. It liked the hoppers’ eggs and for a long time found plenty in Hawaii to stay its appetite. As soon as the leaf-hopper laid its eggs in the cane, this particular insect would appear and lay its eggs in the eggs of the leaf-hopper. When the little enemies hatched out, they fed on the hoppers’ eggs and in turn laid their eggs in the eggs of the hopper. It came to pass that the hoppers, attacked by the parasite on the one hand and by the enemy on the other, rapidly dwindled in number until only a few remained, and these not enough to do material damage. As the hoppers and their eggs diminished, so did the parasite and the enemy, for the latter could live on insect food only.
How the scientists collected these tiny animalcules, kept them alive, transported them thousands of miles across the ocean, bred them in Hawaii and saved the Hawaiian sugar industry, reads like a romance.
The study of entomology is extremely interesting and the every-day business man rarely understands its importance. The finding, breeding and distribution of parasites of insect pests vitally affects the world’s food supply. The entomological name of the leaf-hopper family is _Hemiptera_, and Dr. Sharp, an authority on the subject, has said: “There is probably no order of insects that is so directly connected with the welfare of the human race as the hemiptera; indeed if anything were to exterminate the enemies of hemiptera, we ourselves should probably be starved in the course of a few months.”
It has been estimated by competent authority that the damage done in the world each year by the hemiptera, in spite of all their parasites, is conservatively $600,000,000. Were it not for the parasites, it would only be a year or two at most before every green leaf and spear of grass would disappear from the face of the earth. The direct influence of the practical application of this science to the production of sugar is readily apparent.
Pathology is almost equally important. In former years when cane failed to grow strong and sturdy and did not yield much sugar, the planter usually attributed the difficulty either to lack of water, poor soil, cool weather, too much rain or insufficient cultivation of the field by his manager, when in fact the trouble was due to none of these causes. He would personally oversee the operations of the following year, but with no better results.
When the roots of the cane became matted, stuck together and turned black, when a thick gum exuded from the stalk and leaves, preventing the plant from drawing proper nourishment from the air, it was thought that these troubles arose from climatic or local conditions, while in reality the plant was sick and needed a doctor. Today, under the new régime, whenever the plant shows any symptoms of ill-health, the pathologists are called in to eradicate the disease by scientific treatment.
Insect pests and plant diseases are generally brought into a country through planters sending to other cane-raising countries for new varieties of cane for seeding purposes that they think may produce more sugar than their own. Great trouble and heavy loss have been occasioned in this way and, as a consequence, the United States government has established a strict quarantine, allowing plant life to be landed only after rigid examination and when it is clear that no danger exists.
Another example of the work of the entomologists may be of interest:
During the visit of a well-known Hawaiian to Mexico many years ago, his attention was attracted by a beautiful shrub that he thought would make a splendid hedge around his home. It grew about five feet in height and its foliage was of a rich green, with a brown, red and yellow flower. The slips he brought to Honolulu thrived wonderfully and cuttings of the plant were taken to the other islands for a like purpose. Wherever planted it grew amazingly fast. It quickly spread over the hillsides and became so dense that cattle could not penetrate the thickets formed by it. It made valueless large areas of land that formerly had been used for the pasturing of cattle and plantation stock, and reduced the grazing area at an alarming rate. Land that adjoined the plantations and that in the course of time became needed for plantation purposes was also over-run by it.
The curtailment of the grazing lands and the increased cost of clearing were so great that the entomologists were finally sent for and asked if they could not eradicate the trouble. After a careful investigation they went to Mexico, whence the lantana, as the shrub is called, had come. On their return journey they brought back with them a fly. The fly laid its eggs in the bud of the lantana, and when the young flies were hatched they fed upon the lantana seeds. The flies multiplied rapidly and soon made away with the seeds, thus preventing the shrub from spreading any further. When it was once cleared from the land or the plantation it did not reappear.
These illustrations demonstrate the fact that the culture of sugar cane involves a constant struggle between science and unrestrained nature.
As a rule, Hawaiian sugar plantations are located close to the seacoast, between it and the base of the mountains. The lands slope gently toward the sea, thus insuring good drainage and easy application of water for irrigation. Most of the cane is grown on land less than five hundred feet above sea-level, although in a few rare instances it is cultivated at an elevation as great as three thousand feet. Parts of the leeward side of the islands, where it is extremely dry and hot, and where the cane thrives best, depend entirely on irrigation, the water being brought to the plantations by ditches or pumped from wells. On the windward side of the island of Hawaii, where the rainfall is abundant, irrigation is unnecessary except during very dry periods.
In cultivating, the ground is turned with steam ploughs to depths up to twenty-four inches. These ploughs are operated by powerful engines that work in pairs, one on each side of a field, usually from one thousand to fifteen hundred feet apart. One engine pulls a gang-plough across the field and the other draws it back. By this method the rich soil is thoroughly loosened and a wonderful vegetable growth results. Ordinarily in California the farmer ploughs only from four to six inches deep.
After the lands are ploughed and harrowed and all the weeds turned under, double mould-board ploughs are used to make the furrows in which the seed is planted. The furrows are not like those made for planting potatoes, but are about five feet apart and eighteen inches deep, each furrow and hill being symmetrical. They follow the contour of the land so that the irrigation water will fill the furrow and remain there until it is absorbed by the soil and penetrates to the cane roots. At regular intervals of about thirty-five feet, lateral ditches are cut, from which there is an entrance into every furrow. These lateral ditches deliver the water from the main ditches to the various parts of the fields. The land is now ready for the seed.
Meanwhile, the harvesting of the ripened cane in other fields is going on. As the laborers cut the cane, they top it, that is to say, they cut off about twelve inches of the upper part of the solid stalk. Sugar cane resembles bamboo, in that it is cylindrical in shape and divided every few inches into sections by rings or joints. In every joint there is a bud or eye, from which a shoot of cane will sprout, if properly planted in the ground and watered.
These tops, always cut from untasseled cane, contain very little sugar. They are carried to the newly prepared field and placed in rows in the furrows, end to end, lengthwise, the ends overlapping a trifle in order to guard against blank spaces in the growing cane. They are then covered, according to the season, with one to one and a half inches of earth, and the water is turned in until the furrow contains from three to four inches of water. Between six and ten days afterward, the little green cane shoots appear above the ground. From this time forward continuous irrigation and cultivation, together with proper fertilization, are required until the cane matures.
Planting usually begins in March and continues until September, sometimes later, and the cane ripens one year from the following December.
Growing cane should be watered every seven days, and the amount of water used for this purpose is enormous. For example: a plantation producing thirty-five thousand tons of sugar per annum needs twice as much water per day as the city of San Francisco.
The appearance of growing cane is much like that of Indian corn. The whole field area is covered with a dense, jungle-like vegetation of brilliant green. The leaves are long and narrow and hang in graceful curves. The cane grows so thick that it is almost impossible to crawl through it, and so seldom do the sun’s rays penetrate to the ground that rapid evaporation of the irrigation water cannot take place, hence the cane gets the full benefit of the moisture.
In certain varieties of cane, the great weight of the juice in the stalks causes them to bend, droop and take fantastic shapes. Sometimes they lie on the ground with the ends turned upward, and in fields where the stalks grow to a length of twenty-four feet, the average height of the tops above the ground is not over twelve feet. In other kinds the stalks stand straight up to a height of from eight to fourteen feet.
The production of cane per acre varies in different countries and in different parts of the same country, according to the character of the soil, climatic conditions, care and attention, use of fertilizer and amount of rainfall or irrigation. In Hawaii it ranges from twenty to eighty-five tons, and the amount of sugar obtained per acre runs from two and one-half tons to twelve tons, the average being about five tons.
Broadly speaking, lack of a normal amount of cane per acre, lack of sugar in the cane, or the prevalence of disease, is primarily due to an unsanitary or unsuitable condition of the soil. This can usually be corrected by proper cultural methods, such as adequate aeration of the soil, the turning under of the cane tops and leaves, application of lime and suitable combinations of fertilizing ingredients. Fundamentally, cane requires a well-aerated, moist, alkaline soil and a fertilizer in which the nitrogen content is high and in excess of the potash and phosphoric acid. It is found that nitrate of soda, when applied alone or in combination with potash and phosphoric acid, produces a very strong growth. The proper sanitation of the soil tends to promote the beneficial bacterial action so essential to the growth of the cane.
In December and January the cane tassels or flowers, which indicates that it has about reached maturity and is ready for cutting. Thenceforward very little irrigating is done, as additional water applied at this time might retard ripening, which would mean a reduced amount of sugar stored up in the cane.
It is interesting to note that while the cane is growing and in an unripe state, there is no discernible sucrose or pure sugar in it. As the ripening process goes on, the content of the cane juice is changed by the action of the sun’s rays, and the amount of sucrose as determined by polariscopic test shows when the time for harvesting is at hand. Nature’s operation in thus changing glucose or invert sugar into sucrose or pure sugar cannot be accomplished by any human means.
The harvesting then begins and continues until the end of July or August. Usually the field is set on fire before cutting. On account of the great amount of moisture or juice in the cane, the stalks do not burn, but the leaves are thoroughly consumed. This operation eliminates a good deal of leaf material that is not only useless, but which, if sent to the mill, would increase the cost of crushing, besides absorbing a certain quantity of the juice expressed from the cane.
Formerly men stripped the leaves from the cane in the fields, but it was a difficult matter to accomplish such work, and the cost was heavy. An accident changed the method of doing this work. A field took fire and it was found that while all the leaves were consumed, little or no damage was done to the stalks provided they were cut promptly and sent to the mill to be crushed. The practice of burning has since become general, although the advisability of continuing it is now being given very careful study.
Burning eliminates the arduous labor of stripping, and no doubt does away with many harmful insects and fungi, but at the same time it destroys the enemies and parasites of these insects and this loss is severely felt. Another disadvantage of burning is that the nitrogen contained in the cane leaves is liberated and not returned to the soil as would be the case if the leaves were stripped and ploughed under. In the latter case the leaves rot rapidly, add humus to the soil, help aeration, and improve the sanitary condition, all of which tends to increase the yield of cane per acre. From recent experience it is not improbable that burning will be discontinued in the near future.
As soon as the field is ready, whether burned or not, the laborers go in to cut the cane. A long, heavy knife is used. The cutter grasps the stalk and drives the knife into it, severing it just at the ground. He then tops it, that is, he cuts off the upper part that contains no sugar, and, to aid in subsequent handling, the long stalks are cut into convenient lengths.
As the burning destroys the eyes or buds, certain fields are cut and topped for seed before the burning takes place.
There are two general methods of transporting the cane to the mills. One is by rail and the other by flumes. On the irrigated plantations where water is never overplentiful, railroad tracks and locomotives are invariably employed, while on the non-irrigated plantations, located in districts where there are copious annual rains, V-shaped flumes are extensively used. In some cases a combination of both systems is adopted to advantage. From the upper lands where it is difficult to construct railroads, the cane is flumed to a convenient point on the railroad system, at a lower elevation, and delivered into cars, while the water is conducted into ditches and used for irrigating the lower cane lands.
In the case of rail transportation, paths one hundred and fifty feet apart are cut through the fields so that temporary railroad tracks may be laid and cars run in and loaded on these tracks. The whole field is then cut in the same way and the work continued until the entire crop is harvested.
The loaders follow up the cutters. These men lay a strap on the ground and pile the stalks on the strap until they have a bundle of cane weighing from seventy-five to one hundred pounds. With a dexterity born of long practice, they sling a bundle upon their shoulders and carry it up an inclined runway to a railroad car not over seventy-five feet away and dump it on the car. The cutting and loading are usually done by contract, at so much per ton, and it is remarkable how proficient the men become.
When flumes are used exclusively, much the same methods are adopted. Paths are cut through the fields and in these paths are placed the flumes which, like the temporary railroad tracks, are moved from time to time as necessity demands. The mill is located at the lowest point on the plantation and the flumes are placed so as to insure a good grade from the cane fields on the uplands to the mill below. The flumes are either carried on low trestles or run along the ground, but always at a height which enables the laborers to throw the cane into them conveniently.
Water is turned into the upper end of the flume and, rushing rapidly down, carries or floats the cane to the mill. Cane is flumed in this way for distances up to seven miles at low cost and with satisfactory results.
The cars when loaded in the fields are made up into trains and hauled by locomotives to the mill, which is generally located about the center of the plantation, or at a point where most of the cane can be delivered on a downward grade. Each car is carefully weighed on a track scale and the exact quantity of its load of cane is ascertained and recorded.
For years past the planters have been offering large rewards for the invention of a machine to cut and load the cane, but the old hand method is still employed, although some experimental loading machines are meeting with more or less success, but none are in common use.
The problems involved in cutting cane by machinery seem insurmountable, and, while many devices have been tried, not one has proved successful.
After the cane is cut the first time, ploughs are sent through the fields and a furrow is ploughed along each side of the stubs of the cane which are left in place. This ploughing opens up the ground, aerates the soil, and affords the irrigating or rain water a means of easy access to the cane roots. The water tenders follow up the ploughs and the furrows are filled with water, which is gradually absorbed by the old cane roots left in the ground. In time new sprouts spring up from buds on the old stalks of the cane and another growth begins. The second crop is called “first ratoons” and, when cultivated for a single year only, it is designated “short ratoons.” As a rule it does not yield as much sugar as plant cane, but the saving in seed, in the preparation of the fields and in other labor frequently makes up for the reduced amount of sugar. If allowed to grow for two years, as is generally the case, it is called “long ratoons” and produces proportionately more sugar. In the past a very large percentage of the Hawaiian crop was planted with fresh seed every year and but a small percentage ratooned. Nowadays, however, the tendency is to ratoon the crop as long as the yield justifies, which in many cases is from three to four times. In Cuba the cane when once planted is ratooned for many years.
There have been specific instances in Hawaii where ratoons that have been allowed to grow for two years (long ratoons) have shown a better yield than the first planting. According to the best information, this is due to the presence of poisonous matter in the ground, turned up for the first time at the first planting.
The object of all the ploughing, weeding, cultivating, fertilizing and irrigating, is to produce a large number of strong, sturdy stalks of cane, yielding a maximum amount of sugar. The sugar is contained in solution in the sap or juice and the amount can be materially increased by due care and attention.
As some of the elements which form the plant are absorbed from the air through the leaves, favorable climatic conditions are essential to its full growth and development. Proper fertilizers must be added to the soil, and water applied regularly and in sufficient quantity.
Commercial fertilizers are used in Hawaii probably to a greater extent than in any other country in the world. It is quite common for plantations to use half a ton of fertilizer per acre per crop, and at times as much as two thousand pounds per acre. The yearly fertilizer cost per acre will probably average twenty-five dollars.
As it takes eighteen months for a crop to mature in Hawaii, it will readily be seen that the plantation area must be at least double that used for any one crop. While one crop is being harvested, another crop is in the ground growing. As soon as the cane is cut, the lands are immediately prepared for replanting or ratooning, as the case may be. During certain periods each year, usually in June and July, a visitor on an Hawaiian plantation can see one crop growing, one being harvested and one being planted.
From the foregoing it will be seen that the harvesting begins in December and ends in July or August. The planting begins from March to June and usually ends in September, according to plantation conditions and whether or not the land is irrigated.
THE MANUFACTURE OF RAW SUGAR
The details of the manufacture of raw sugar from cane and of sugar from beet roots differ, but there are several processes common to both. The operations necessary for making raw cane sugar are as follows:
1. The extraction of the juice. 2. The purification of the juice. 3. The evaporation of the juice to syrup point. 4. The concentration and crystallization of the syrup. 5. The preparation of the crystals or grains for the market by separating them from the molasses.
Every mill has an extensive laboratory where skilled chemists are constantly engaged in sampling and analyzing cane, raw juices, syrups, sugars and molasses. In fact the chemical work is a most important feature in the raw-sugar house, beet-sugar factory or refinery. The superintendent should be an expert chemist, as the proper recovery of the sugar from the cane and beet juices is wholly dependent upon the technical control of manufacturing processes.
EXTRACTION
After passing the scales, the cars containing the cane are switched alongside the carrier which feeds the cane into the mills. Before the cane is unloaded, however, samples are taken from each car and sent to the laboratory, where they are carefully analyzed. The amount of sugar present is ascertained, as well as the quantity and quality of the juice in the cane. It is, however, impossible to get a fair average sample of the cane in this way, and therefore the efficiency of the mill work is determined on the basis of an analysis of the juice and the fiber after it has passed through the crushers.
The carrier just referred to is a wide slat conveyor, running alongside the railroad tracks in the yards to a point directly over the first set of crushers. The cane is taken from the cars by a mechanical unloader, the arms of which reach out and with distended fingers pull the cane stalks off and land them on the slow-moving carrier, which takes them onward and upward to the crusher.
The crusher consists of two large rolls, with immense interlocking, corrugated teeth on the circumference of each. These rolls are set close together, and the cane passing through is broken into short pieces and matted to an even layer. The juice squeezed out by this preliminary crushing runs through a metal trough into a large receptacle known as the juice tank.
From the crusher the mat of cane passes to the mills proper. These mills consist of from nine to eighteen rolls, about thirty-four inches in diameter and seventy-eight inches long, arranged in groups of three, set in the form of an isosceles triangle, one above and two below, one set following the other in a direct line. The lower rolls are parted enough to allow the expressed juice to fall through them, while the half-crushed cane is carried over by means of an iron bar called the returner. The faces of the rolls are more or less roughened, or grooved, so as to draw the cane through and give a better crushing action. They are turned slowly by powerful engines, which transmit the power to each set of rolls through a system of gears. The rolls are forced together by hydraulic rams exerting a pressure of from four hundred to six hundred tons. It is this tremendous pressure that squeezes the sugar-bearing juice out of the cane.
From the crusher the matted cane passes through the first set of rolls, where a large percentage of the remaining juice is liberated. This is caught in a metal trough and, after passing over a fine screen to remove the small pieces of cane, runs to the juice tank. The cane passes through the second set of rolls, thence to the third set, and so on to the end of the mill. In front of the last set of rolls, hot water is sprayed on the cane to soften the fiber and dilute the remaining juice, thus aiding the final extraction. The adding of hot water is termed _maceration_. By the time the cane has passed through the last set of rolls, all the economically recoverable juice is out of it and delivered into the juice tank, with the exception of the juice and maceration water from the last set of rolls, which is always returned to the preceding set of rolls for maceration purposes. The juice or maceration water coming from the last set of rolls contains very little sugar, and the object is to secure greater concentration by using it for double maceration instead of adding that much additional water which would have to be evaporated later on in the process.
In well-designed, modern mills, with cane carrying not over twelve per cent of fiber, more than ninety-eight per cent of the sugar in the cane is extracted, the remainder being left in the fiber. This is almost perfection today. What it will be tomorrow no one can say.
The fibrous, woody part of the cane, or bagasse as it is called, is comparatively dry as it leaves the last rolls. It is conveyed from the mills to the boiler house on a wide slat conveyor, and fed directly into the furnaces under the boilers that generate the steam for power and boiling purposes. A modern raw-sugar mill requires practically no other fuel than that obtained as a by-product from the crushing of the cane.
The boiler plant is usually of large capacity, as a great deal of steam is required to drive the engines that run the crusher, the rolls, the electric lighting system, the pumps and other machinery. Besides, a large amount is needed to evaporate the water in the juice and to boil and dry the sugar. The ashes from the furnaces are returned to the fields as fertilizer, so that very little is lost.
PURIFICATION
The juice as it comes from the mills contains impurities such as dirt from the fields, small pieces of cane stalks and other foreign matter, besides salts, gum, wax and albumen. It is necessary to remove as many of these substances as possible, and this is where the chemist’s work begins.
So long as the juice is confined in the living cells of the cane it does not quickly ferment, but when liberated it rapidly undergoes such change. Therefore no time is lost in arresting this action. The juice is pumped to the top floor of the mill and there a solution of milk of lime is added in sufficient proportions to neutralize the acidity. The mixture is then heated in closed tanks under pressure to 215 degrees Fahrenheit. The heat causes the lime to combine rapidly with the gums and salts in the juice, and the albumen to coagulate.
The hot juice is then run into large settling tanks, where the insoluble solids and the albumen sink to the bottom, carrying with them vegetable and other matter suspended in the juice. Certain foreign substances of light specific gravity float to the surface in the form of scum.
After settling for a time the clear juice is drawn off and the scum, mud and cloudy liquor left in the tank. As a vast amount of liquor must be handled every hour, it is not practicable to have tank capacity great enough to admit of the liquor standing a sufficient length of time for every particle of foreign matter to settle, so as an adjunct to the settling tank, filters are used. These are cylindrical iron tanks, packed tightly with ordinary wood fiber, known as excelsior. The juice is conducted to these filters, and as it percolates through the excelsior, practically all of the remaining foreign matter is caught and retained in the fiber. The clear juice is then run to the receiving tanks for the evaporators and the mud and scum that remain are drawn off into mud tanks, where more lime is added and the mass stirred up. Finally it is delivered to the filter presses, where the mud and other impurities are taken out and the clear liquor containing sugar is sent to the evaporators.
Another method for cleaning, called “precipitation in motion,” is to carefully lime the juice and then heat it in closed vessels and under sufficient pressure to carry it through a pipe to large insulated settling tanks.
These settling tanks, usually of sheet steel, are made in the form of truncated cones with conical bottoms, the small diameter of the tank being at the top. Suspended in the center is a vertical cylinder somewhat less in diameter than the upper part of the tank. This cylinder extends downward about eight feet to a point opposite the largest diameter, which makes the area between the circumference of the suspended cylinder and the tank at that point very much greater than the area of the cylinder itself. This difference in area is necessary to retard the flow of the juice and allow the sediment, mud and insoluble solids to be deposited at the bottom of the tank.
The juice is delivered by a pipe into the top of the cylinder which projects a few inches above the edge of the surrounding settling tank. It passes slowly down the central passageway, turns at the bottom, where its speed is materially slackened, and goes out through a pipe line connected to the side of the tank just below the upper edge.
There are several other methods in general use, but in all of them the principle of settling, upon which the separation or cleaning depends, is the difference in specific gravity between the juice and the dirt. A high and even temperature should be maintained by preventing radiation, as lowering the temperature would increase the specific gravity and viscosity of the juice without increasing that of the dirt in equal proportion.
There are many different types of filter presses, but those at present in general use are long, oblong machines, set horizontally on the floors, with layers of corrugated iron plates, covered with canvas sheets, between which are hollow frames so arranged that the juice will pass from the hollow frames through the canvas to the corrugations in the plates.
In passing through the presses under pressure the sediment, scum and other impurities are caught on the canvas sheets and the clear juice passes through the canvas, down the corrugations and out through small holes in the plates controlled by valves on the outside of the presses, from whence it runs to the evaporator tanks. The sugar in the mud caught in the hollow frames is washed out of the mud with water and is sent to the evaporator, while the mud itself is finally returned to the field, to be used as a fertilizer.
The clarified juice from the settling tanks, filters or presses, is light brown in color, but is thin and watery, and must now be reduced to syrup point. All the suspended impurities have been removed, but some impurities in solution and the original coloring matter still remain. Some of these foreign substances are subsequently eliminated during the process of crystallization in the vacuum pans described later on.
The object to be attained in a raw-sugar house is the production of a sugar containing ninety-six per cent of sucrose, and there is little or nothing to be gained by carrying the process of manufacture beyond the stage that insures such result.
The final extraction of all the impurities and the conversion of the impure raw into pure white granulated sugar is the work of the refiner, which is dealt with in a subsequent chapter.
From the time the juice leaves the cane until it is crystallized it is kept at a high temperature, as cold juices or syrups are viscous and run slowly. High temperatures kill germs, prevent fermentation and expedite manipulation.
EVAPORATION
Under ordinary atmospheric pressure at sea-level, water boils at a temperature of 212 degrees Fahrenheit and sugar juice at a few degrees higher, according to its density. This temperature if long applied to sugar juice would tend to burn and destroy the sugar, but the juice can be heated to 250 degrees for a short time without deterioration.
The clarified juice contains about eighty-five per cent of water and fifteen per cent of solid matter. A large proportion of the water must be removed by evaporation. To accomplish this under ordinary atmospheric conditions would require heat increasing from 212 degrees Fahrenheit, as the solution increased in specific gravity above the standard of pure water. This would require a large amount of fuel, and the juice would also be more or less adversely affected by long maintenance of comparatively high temperature.
To obviate these conditions the juice is boiled in a multiple evaporator, the invention of Norberto Rillieux, whose first construction in New Orleans in 1840 was a double effect horizontal submerged tube apparatus which has since undergone many changes and improvements. The theory of evaporation _in vacuo_ was extended to two or more cells or vacuum bodies, using the steam or vapor from the first to heat the juice or syrup in the second and so on. At the present time the quadruple effect, or four-cell evaporator, is most commonly in use, although sextuple effects are not rare. The ordinary practice is as follows:
The juice enters cell No. 1 and covers the heating tubes, to which is admitted sufficient steam—generally exhaust from the engines—to cause the liquid to boil. The steam or vapor liberated from this first boiling is conducted through the vapor pipe directly into the heating tubes of cell No. 2, while the juice from cell No. 1 is passed into the second, or cell No. 2, and surrounds the heating surfaces which contain the hot vapor given off from the same juice in cell No. 1.
As there is little or no pressure above the liquid in the first cell, the juice boils at from 215 degrees to 220 degrees Fahrenheit. By maintaining a vacuum of five inches in the second cell, the temperature at which the liquid will boil is reduced to 203 degrees, and the vapor from cell No. 1 is hot enough to boil the juice in cell No. 2 without any addition of heat. The vapor from cell No. 2 in the same way enters the heating tubes of cell No. 3, while the juice entering this cell is exposed to a vacuum of fifteen inches, which reduces the boiling temperature to 180 degrees, so that the difference of 23 degrees between the conditions of cell No. 2 and cell No. 3 causes a third boiling and evaporation without any additional steam being added.
A vacuum of twenty-six inches in the last cell, No. 4, brings the final boiling temperature down to about 150 degrees. The vapor from this last cell enters a condenser, where it is exposed to a spray of cold water, is condensed and passes down a pipe not less than thirty-four feet long, terminating in a water seal, and called the Torricellian tube, after Torricelli, who discovered that mercury would rise thirty inches in a tube while water would rise thirty-four feet with a perfect vacuum.
The juice in passing through these evaporating cells is boiled to a syrup containing about thirty-five per cent of water and sixty-five per cent of solid matter. It is pumped out of the fourth cell into the receiving tank for the vacuum pan.
This quadruple system of boiling only requires about one-fourth the amount of heat that would be necessary to do the same work in a single vessel. As the evaporators operate continuously, a constant level of the boiling liquid is maintained in each cell, the juice being drawn from one to the other by increasing vacuum and controlled or regulated by means of valves.
A powerful vacuum pump draws the air and other incondensable gases from the condenser and maintains the vacuum, which is applied to the necessary extent in each cell. The heating tubes are connected to drain pipes, which remove the condensed vapors.
Vacuum, simply and concisely stated, is the absence of air or gas. It is usually obtained by pumps which suck the air or gas out of closed containers or pipes. No doubt many of the readers in their younger days have sucked on the end of a bottle and were amused to find the bottle hanging on the end of the tongue. It was the vacuum, or lack of air in the bottle, which caused it to hang thus. The outside atmospheric pressure (which at sea-level is fifteen pounds per square inch) was doing its best to gain an entrance through the tongue into the bottle from which the air had been extracted.
The pumps simply suck the air out of the containers or pipes and discharge it through valves, in much the same way that the air was sucked out of the bottle. It must be remembered, however, that in boiling water or juice, the vacuum is being continually broken or reduced by the liberation of air and gases from the juice, steam and condensing water. This action must be overcome by the constant work of the vacuum pump.
To determine the amount of vacuum carried in any container, a small mechanical contrivance, known as a vacuum gauge, is used. This, in its simplest form, is a bowl of mercury with a long glass tube leading from it. If the upper end of the glass tube is attached to the container from which the air is to be drawn, the mercury in the tube will rise in proportion to the amount of air extracted. When an absolute vacuum has been formed, the mercury in the glass will stand at a height of thirty inches.
In commercial operations a vacuum greater than twenty-eight inches is seldom required, as this is sufficient for all practical purposes. The degree of vacuum for any container can be varied easily by mechanical manipulation, so that a vacuum anywhere from one to twenty-eight inches may be maintained.
CONCENTRATION AND CRYSTALLIZATION
From the receiving tanks the syrup is drawn into the pans by a vacuum ranging between twenty-five and twenty-seven inches. The pans are large cast-iron or copper cylinders, standing in a vertical position, with dome-like tops and conical bottoms, almost spherical in shape. Leading from the top is a large pipe through which the vapors from the boiling are drawn off and condensed. On the conical bottom is a large valve, which may be opened when the boiling is finished to allow the _massecuite_ (a French term meaning cooked mass) to drop out.
At regular intervals in the height of the pan there is a series of copper coils, connected with a steam line at one end and a drain line at the other.
The general principle involved in boiling sugar is the separation of the sucrose contained in a solution from the impurities present in that solution, and this is accomplished by evaporation and concentration through the agency of heat. After the sugar is once formed in definite crystals these crystals attract and appropriate the sucrose in solution in the process of building up the crystal structure, while repelling or excluding the impurities, so that, as a consequence, the latter remain in solution. The crystals thus formed are subsequently removed from the solution by means of centrifugal machines. Crystallization, whether in a pure or impure solution, will proceed to only a certain extent, and will only partially remove the sucrose from the solution in one boiling, the limit of crystallization being governed by the amount and nature of impurities present.
The process of boiling is begun by drawing some of the concentrated juice into the pan and turning steam into the coils, which starts the boiling. This is continued until the supersaturation is such that minute crystals of sugar form or “grain out.” By properly timed admissions of fresh concentrated juice, drawn into the pan by vacuum as before, the crystals grow in size and at last the pan becomes filled with a mass of sugar crystals of regular shape and size, immersed in a thick “mother liquor” containing sugar and the impurities that were not removed by the filters or settling tanks.
The size of the grain may be varied at will by the operator in charge, who is known as the sugar boiler. After the grains are once formed, their number (if the sugar boiler is an expert) does not increase, but the size does, as the original grain continually builds up on itself from the outside.
The question may be asked, why is all the moisture not boiled out in the pan and the sugar dropped in a dry, crystallized state? There are several reasons why such a course is impracticable; first, because the impurities, which must be eliminated by crystallization and which are carried off in the mother-liquor, would be boiled into the sugar and make it unsalable; second, because to aid crystallization and prevent scorching or burning on the hot steam coils the mass must be kept in active circulation during the boiling process, or, long before all the moisture could be driven off, a large part of the contents of the pan would be burned on the coils; and third, even if it were practicable to boil the contents down to a solid state, the grains would stick to each other and become one solid mass, which would have to be removed from the pan with bars, picks or chisels. Enough moisture, or rather liquor, is left in the mass to enable it to flow from the pan by gravity. This liquor, with the impurities it carries, is subsequently removed from the sugar by a drying or separating process which will be explained later on.
Massecuite is a viscous, sticky, semi-fluid mass of the consistency of half-formed ice.
The reason sugar “grains” is because the water in the juice has the power to hold in solution only so much sugar. As it goes into the pan, the juice is almost a saturated solution, and as the water is driven off by evaporation, the solids that up to this point have been in solution must of necessity crystallize.
When the sugar boiler decides that the “strike,” that is, the massecuite contained in the pan at one boiling, is satisfactorily grained, he breaks the vacuum by opening a valve on the top of the pan, thus allowing the air to enter. He then opens the valve at the bottom of the pan and the mass drops into a long tank with a rounded bottom, called the mixer, in which a shaft, equipped with paddles, is revolving. The paddles are for the purpose of keeping the mass agitated and in an even condition. The agitation prevents the grains from dropping to the bottom of the tank and forming a solid block, called concrete.
PREPARATION OF CRYSTALS FOR THE MARKET
From the mixer the massecuite runs through spouts into the centrifugal machines. Centrifugal machines are cylindrical-shaped, perforated brass baskets, usually forty inches in diameter and twenty-four inches deep, hung on a central shaft suspended from beams overhead, and surrounded by a solid outside curb or casing.
On the shaft is a pulley, which is driven by a belt connected with an engine or an electric motor. The inside of the basket is lined with a fine-meshed brass screen, which retains the grains of sugar, but allows the liquor to escape freely into the outer casing.
As soon as the centrifugal machine is filled with massecuite from the mixer above, the power is turned on and the machine begins to spin around at an increasing speed until a velocity of one thousand revolutions per minute is reached. The centrifugal action forces practically all the liquor out through the screen and leaves in the machine all the grains of sugar that were formed in the pan. A little dry steam is sometimes turned in to assist in reducing the moisture in the sugar.
The centrifugal is then stopped, a valve in the bottom is opened, and the nearly dry crystallized raw sugar is dropped into bins. From the bins it is drawn off through spouts and packed in sacks containing about one hundred and twenty-five pounds each.
It has been demonstrated that raw sugar containing a large amount of moisture inverts or deteriorates more rapidly than that with a low-moisture content. It is apparent that as moisture adds to the weight, the transportation charges, which are based on tonnage, are greater in the case of wet sugar than in the case of dry. In many of the modern mills, therefore, a further treatment is given the sugar to reduce loss by inversion and lessen freight charges.
From the bins last mentioned the sugar is dropped into revolving drums six feet in diameter and twenty-six feet long, set at an incline so that as the drum revolves the sugar is carried round to the highest point on the circumference of the drum and dropped to the lower side, at the same time traveling from the receiving to the discharging end. The shape, motion and inclined position of the drum cause a perfect shower of sugar in the drum for its entire length and breadth. While it is revolving a current of hot, dry air is drawn through the drum by means of suction fans, and as a result the moisture in the sugar is absorbed by the air and carried out of the building. At this stage the product has a good hard grain of a yellowish-brown color; contains from ninety-six to ninety-seven per cent of pure sugar and about one-half of one per cent of moisture.
From the end of the revolving drum the sugar is drawn off into sacks holding about one hundred and twenty-five pounds each. These sacks are sewed by machinery and put into railroad cars to be hauled to the docks at the shipping port, where the cars are switched under huge hoisting cranes or alongside speedy conveyors which carry the sugar into large seagoing steamers especially built for the trade. Some of these ships have a cargo capacity of two hundred and twenty thousand sacks, and they transport the sugar to the buyers on the mainland in San Francisco, New York or Philadelphia, as the planter directs.
The liquor thrown off by the centrifugals is not lost; it is taken back to the pans and reboiled. After this has been done several times and most of the sugar extracted, the purity is so low and the sugar content so small that it does not pay commercially to reboil further, and the residue is sold as molasses. It contains about thirty-five per cent of sugar and from twelve to fourteen per cent of invert sugar, or glucose, as it is generally called.
Some of the waste molasses is mixed with fodder and tender cane tops and fed to cattle and plantation stock, the sugar content proving of great value as a fattening agent and energy builder. Part of the molasses is sprayed on the bagasse as it leaves the crushers and serves, first, as a fuel under the boilers, and, second, as a fertilizing agent in the form of ashes after it has been burned. During the past few years much of it has been shipped in tank steamers to the mainland, where it is used for the manufacture of spirits and vinegar, and also as the principal ingredient in prepared stock foods which are much in demand today.
Every bag of sugar shipped from the plantation is marked to indicate the plantation from which it came. The net weight of the sugar in each bag is recorded, a sample of the sugar taken and its sucrose content ascertained, for it is on the basis of weight and sucrose content that raw sugar is bought and sold.
From the beginning to the end of the process of manufacture, chemists are vigilantly alert sampling, testing, analyzing and supervising the operations. Records are made of all analyses, temperatures, purities, densities, extractions, etc., and the results tabulated for future reference.
The average cost in Hawaii of preparing the fields, planting, irrigating, fertilizing, cultivating and cutting the cane, manufacturing the sugar and delivering it in the New York market, is about $56.00 per ton of two thousand pounds.
TRANSPORTATION AND DELIVERY OF RAW SUGAR
It has been explained that in Hawaii sugar is packed in one-hundred-and-twenty-five-pound sacks. Methods and customs vary in different countries. For instance, in Cuba it is put up in large gunny bags, each holding an average of three hundred and twenty-five pounds. The same custom prevails in Porto Rico. In Peru, and to a limited extent in Java, sacks containing two hundred and twenty-four pounds are used. A large part of the sugar in Java, however, is put up in bamboo baskets of native make, containing from five hundred to eight hundred pounds. They are about thirty inches in diameter, from thirty-six to forty-eight inches high, and are lined with coarse leaves to prevent the sugar from sifting out between the weavings of the bamboo. Philippine sugar is packed in leaf-lined mats of tough vegetable fiber, each holding about seventy pounds.
These various styles of containers necessitate different methods of handling to and from the ships and by the buyers, but Hawaii will again serve as an example of efficient, modern practice. Outside of what is consumed locally, all Hawaiian sugars are shipped to the mainland of the United States by steamers or sailing vessels to San Francisco, or by steamers to New York or Philadelphia, via the Panama canal.
As sailing vessels are rapidly disappearing from the seas so far as the sugar trade is concerned, reference will be made to steamer traffic only. The steamers are specially built for carrying sugar, having a cargo capacity of from five thousand to thirteen thousand tons, and the best loading and discharging facilities.
When loading in Honolulu, the steamers usually lie alongside wharves covered with immense warehouses, where rapid-speed conveyors carry the sacks of sugar to a point above the ship’s hatches and drop them into chutes which guide them down into the hold of the ship, where they are compactly stowed. On the off-shore side of the vessel small steamers from other island ports lie alongside and hoist the sacks by means of steam winches to a point over the hatch and deposit them in similar chutes. When steamers are loaded from both sides in this manner, as much as three thousand tons, or forty-eight thousand sacks, can be loaded in nine hours.
After a vessel is completely loaded and gets her clearance from the custom house, she departs for San Francisco, twenty-one hundred miles away, or for the Atlantic seaboard, via Panama, as the planter may direct.
The voyage ended, and the quarantine and health regulations complied with, she proceeds to the dock of the buyer, usually a sugar refiner. The Hawaiian planter invariably sells his sugar under contract prior to arrival of the vessel at destination.
Planters in other countries operate differently. Occasionally sugar is sold on the plantation at an agreed price, and the buyer arranges his own transportation. The planter sometimes ships his sugar unsold and negotiates its sale while it is en route. If so sold, it is delivered directly to the buyer on arrival; if not, it must be stored in a warehouse at the planter’s expense pending sale.
The practice of the Hawaiian planter is to sell his sugar to refineries in San Francisco, New York or Philadelphia, under contracts extending over a term of years. It is agreed that the sugar shall be shipped as soon as made and that the refiner will receive it immediately on arrival, the price for each cargo being that quoted in the open New York market for ninety-six-degree centrifugal sugar on the day preceding its arrival.
The value of raw sugar, like that of other staples, is based on supply and demand, and the price fluctuates from day to day according to the requirements of the refiners or the necessities of the sellers.
There are certain rules or trade conditions governing all sales, so that when one man buys and another sells at an agreed price, each knows what he is bargaining for. For instance, raw sugar is bought on the ninety-six-degree centrifugal basis, that is, the price agreed to be paid is for centrifugal sugar containing ninety-six per cent of sucrose. If it contains more sucrose, a higher price is paid; if it contains less, a lower price is paid; all according to an established scale of additions and deductions. Then again, the time of payment for the sugar is well understood. It is usually ten days after the sugar has been finally discharged from the ship, as this allows a sufficient period in which to determine the exact weight of the sugar and the percentage of sucrose it contains. An instrument called a polariscope is invariably employed to determine the amount of sucrose present and the results obtained from its use are absolutely accurate. A description of the operation will undoubtedly prove interesting.
POLARIZATION
The practical working of the polariscope is based upon the property of sucrose to rotate a ray of polarized light to the right.
Ordinary light is the effect on the eye of vibrations of the ether. These vibrations occur in all directions, but by certain optical devices they may be confined to a single plane, and light thus confined is called polarized. If rays of polarized light pass through a layer of certain bodies, _e. g._, quartz, sugar and many others, the plane in which the vibrations occur is rotated, and the polariscope has been devised for the purpose of measuring the rotation of the plane of polarization.
Polarized light, as used in the polariscope, is obtained from the Nicol prism or some development of it. Ordinary light passing through crystals of certain bodies, of which Iceland spar is an example, is split into two rays, one of which is known as the ordinary and the other as the extraordinary ray. A Nicol prism is made of two wedge-shaped pieces of Iceland spar, cemented together with a film of Canada balsam.
The accompanying sketch gives a good idea of the arrangement of an ordinary polariscope.
A strong white light, _e_, enters the instrument through a lens at _f_, to the Nicol prism _b_, by which it is polarized. The ordinary ray is dispersed, while the extraordinary or polarized ray passes straight through and enters the sugar solution contained in the tube _c_, which has glass ends. In passing through this solution it is given a rotary motion to the right or to the left, according as the sugar in the solution is sucrose or levulose. When it emerges from the tube containing the sugar solution, the now rotated polarized ray encounters a second Nicol prism, of which one of the wedges is fixed and the other movable. This prism is called the analyzer. A pointer, controlled by a thumb screw, is attached to it, and when the correction of the polarized ray’s rotation has been made with precision by adjustment of the wedges, the pointer will indicate directly and accurately on a scale the amount of sucrose in the solution under test, because the polarized ray was rotated in exact proportion to the amount of sucrose contained in the solution through which it passed.
The polariscope is made and set so that a standard weight of pure sugar (C₁₂H₂₂O₁₁), dissolved in a standard quantity of pure water, and placed in a tube of given length, will rotate the ray of polarized light in passing through, to a point on the scale marked one hundred degrees, the equivalent of per cent. Also, that by using the same quantity of water, but twenty-five per cent, fifty per cent, or seventy-five per cent less weight of sugar, the rotation will show seventy-five degrees, fifty degrees or twenty-five degrees of pure sugar, as the case may be.
A sample is drawn from each bag of sugar and all of these go to make up a general average sample. The standard quantity is carefully weighed, dissolved with the standard amount of water, clarified, filtered and poured into a tube with glass ends, which is then inserted in the polariscope between the eye of the operator and a strong artificial light. When the operator making the test applies his eye to the instrument, he sees a distinct shadow on a lens in the line of vision, one side being light and the other dark. He then turns the thumb screw which adjusts the analyzer until the whole field of vision is neutral, which indicates that the rotation of the polarized ray has been corrected. The pointer on the scale now shows the exact percentage of sucrose present in the raw sugar, ninety-four, ninety-five, ninety-six degrees, or whatever it may be. This test determines the real value of the sugar, based on the market quotation for ninety-six-degree sugar. If the polarization should show exactly ninety-six degrees, the price to be paid for the sugar and the market quotation will be identical.
In most sugar-producing countries the government imposes an import tax on all foreign sugars, in order to obtain revenue to defray governmental expenses and to protect the domestic industry, if any, against competition with other countries in which cost of materials and labor may be lower. Commodities produced in a country naturally add to its development and wealth, and this explains the fostering of the sugar industry by various governments.
The United States duty on foreign sugar is at present $1.256 per one hundred pounds of ninety-six-degree raw sugar. On account of our treaties with Cuba, the Cuban planter is allowed a deduction of twenty per cent, and, therefore, pays a duty of $1.0048 per hundred pounds, which, owing to trade conditions, is the duty effective today in the United States.
Sugars produced in the insular possessions, Porto Rico and the Philippine islands, are admitted free of duty.
In 1898, the Hawaiian islands, through annexation, became a part of the United States, consequently no duty is assessed on sugar or any other Hawaiian product.
Every vessel coming into a port of the United States must be entered at the custom house, where a record is kept of the port whence she came and of what her cargo consists. If from a domestic port, she is permitted to discharge her cargo without delay; if from a foreign one, customs officials are immediately sent on board to watch the cargo as it is discharged and supervise the tallying, checking or weighing, according to the class of merchandise. Besides being weighed, sugar is carefully sampled and the percentage of sucrose ascertained by the polariscope, for the customs duty is based upon the purity of the sugar, all raws testing not above seventy-five degrees polarization paying .71 cent per pound and .026 cent per pound for each additional degree. This is equivalent to 1.256 cents per pound for ninety-six-degree sugar.
The people of the United States used 4,257,714 short tons of sugar in the year 1915. It was nearly all produced within the United States or in countries enjoying tariff concessions, as follows:
SHORT TONS Hawaiian islands (Cane) 570,375, U. S. territory. Louisiana (Cane) 251,740, U. S. territory. Domestic production (Beet) 861,568, U. S. territory. ” ” (Maple) 17,248, U. S. territory. Porto Rico (Cane) 336,347, insular possession. Philippine islands (Cane) 134,626, insular possession. Cuba (Cane) 2,062,594, reciprocity treaty. Foreign sugar (Cane) 23,216, full duty-paying. ---------- 4,257,714
Aside from the small amount of full-duty-paying foreign sugar imported, the only sugar in the above list that paid duty came from Cuba. It is evident, therefore, that under ordinary conditions an increase in the crops of any of the places mentioned would result in a surplus of sugar in the American market. In 1916, with the beet production of Continental Europe locked up by the war, Cuba’s increased output has been absorbed by Great Britain, France, Italy and Greece.
Steamers from Hawaiian ports, after arriving and entering at the custom house and passing quarantine and health officers, proceed immediately to refinery docks to discharge cargo.
REFINING OF RAW SUGAR
Cane-sugar refineries are always located in great seaport towns for the reason that, as practically all cane sugar is grown in the tropics, it must be transported by water to the world’s markets.
The refining operation is by no means as simple as may at first appear. It is essential that the finished product be almost chemically pure (99.8 per cent), and the greatest care must be exercised to obtain a perfectly white color, as well as a hard, lustrous grain.
The question naturally arises, why do not the planters of Hawaii, Cuba, Java and other raw-sugar-producing countries carry their process a few steps further and make a pure white sugar as the refiners do? This has been attempted many times, but has almost always been found impracticable, notwithstanding the fact that there is no mechanical or chemical reason why.
Among the arguments in favor of a mainland seaport site, the following may be mentioned:
1. The producing centers are generally far distant from consuming markets. Refineries located in the tropics would be under unusual expense for transporting and selling the refined article.
2. A refinery in the tropics would be out of direct and prompt touch with the individual requirements of the buyers.
3. Refined sugar should be moved and sold as soon as possible after its manufacture, so there follows the necessity for adequate dock and rail facilities as means of quick communication with the market.
4. An abundant supply of pure, soft water for refining purposes, and salt or fresh water for condensing, as well as fuel for the generating of steam, must be readily available. Another most important requisite is skilled labor, which is more easily obtained in populous seaport cities than in the small, isolated towns of the tropics.
5. There are many commodities used in the refining of sugar and in packing it for shipment that can be purchased more advantageously, both as regards price and promptness of delivery, in the great commercial ports than in the sugar-growing districts. Among these are bone-char, lime, acids, cotton filter-bags, burlap, cotton cloth, boxes, barrels, cartons, iron, steel and machinery of all kinds.
6. A sugar refinery is operated the entire twelve months of the year, while a raw-sugar mill must of necessity take care of the crop of cane in about eight months. To refine sugar where it is grown would require refining machinery capable of handling the entire output in the eight-month period, and during the remaining four months the plant would remain idle. This would mean a larger investment proportionately than that made in a refinery in a consuming center, running steadily the year round.
7. Refined sugar very rapidly absorbs moisture, and while in transit from the tropic to the temperate zone it is very apt to become lumpy or caked, which would involve reprocessing at great expense at the point of consumption. The unavoidable damage to the packages in loading and discharging results in heavy expense, as all packages must be delivered to the buyer in first-class condition. To avoid hardening, refined sugar should never be piled very high, and it is an unsolved problem whether refined sugar will stand long ocean transportation in cargo lots without caking and damage by breaking of the inside cotton sacks. If shipped in barrels, the freight rate is proportionately higher.
8. Larger capital would also be required, as refined sugar must be carried on hand and must await the consumer’s demand, while raw sugar generally has a prompt and ready market and can be quickly converted into cash.
With these difficulties presenting themselves to a prospective sugar refiner in a raw-sugar-producing country, the shipping of raw sugar to refineries at great distances does not seem at all unreasonable.
Raw sugars show considerable variance in their component parts, and so it follows that some are less easily refined than others. Such differences are generally due to diverse methods of culture, amount of fertilizer used, the processes of manufacture and the efficiency of extraction. If the extraction be high, a large percentage of the salts in the cane is taken up, and these salts prevent or retard the complete crystallization of the pure sugar in refining. One part of ash prevents several times its own weight of sugar from crystallizing, hence it is readily seen that raw sugars with a low ash content are preferred by refiners.
Sugar refining is the production of pure white sugar in granular form, after the removal of the impurities from the raw product. Nine operations are necessary to bring about this result:
1. _Washing_:
Removal of superfluous impurities.
2. _Melting_:
Changing the solid raw sugar into liquid form by melting with water.
3. _Defecation_:
Precipitation of suspended and insoluble impurities.
4. _Bag and Bone-char Filtration_:
Removal of suspended impurities, color and soluble impurities.
5. _Crystallization_:
Production of crystals by concentration.
6. _Partial Drying_:
Purging crystals from syrup in centrifugals.
7. _Final Drying_:
The driving off of all remaining moisture.
8. _Sorting of Crystals_:
Sorting of grains according to size to meet market demands.
9. _Packing_:
Putting in various forms of containers.
A refinery consists of a group of buildings, each of which has been constructed for a special purpose and for convenience and economy in operation. They are as follows:
1. The melt or wash house. 2. The char house. 3. The pan house. 4. The packing house. 5. The boiler house. 6. The pump and power house.
In addition there are offices, shops, laboratories, and last, but by no means least, very extensive warehouses.
To begin at the beginning it will be necessary to start with the steamer laden with raw sugar and made fast to the wharf in front of the warehouse that forms part of the refining plant.
The sugar is hoisted out of the ships in sling-loads by powerful winches, and landed on a platform on the dock alongside the ship. Each sling-load consists of from twelve to twenty sacks, or the equivalent weight in baskets or mats, as the case may be. As soon as the sacks are landed, they are sorted according to mark, put on trucks to be run over a scale set in the floor, and their gross weight recorded.
As the truck leaves the scale, the samplers take a sample from each sack. This is done with a tryer, a long, hollow steel tube, open on one side and sharp at one end, with a handle on the other for the sampler to grasp when forcing the tryer into the sack. The individual sample from each sack of each different mark is deposited in large closed cans until the cargo is completely discharged, when an average sample of all the individual samples of each mark is made up and used in the laboratory to determine the polarization or sucrose content of the various lots comprising the entire cargo. The value of the sugar is fixed by this polarization.
The weights of the various truck-loads of sugar passing over the scales are totaled and the weight of the sacks, baskets or mats deducted, giving the net weight of the sugar.
Hawaiian sacks weigh exactly one pound; Cuban, Javan and Peruvian sacks about three and one-half pounds. Javan baskets weigh from twelve to fifteen pounds, and Philippine mats about four pounds.
In order to facilitate the weighing and simplify the calculations, in cases where the exact weight of the sacks is known, every truck is made to weigh the same by ascertaining the weight of the heaviest and then putting small iron nuts or washers on the rods of the other trucks until each of them exactly counterbalances the heaviest. One truck is then placed on the scale and the scale is brought to a perfect balance, just as though there were no truck on it. In this way the weight of the truck is never recorded, which greatly simplifies the entire weighing operation.
One crew of men will discharge from 1300 to 1500 sacks of sugar per hour from each hatch of a steamer, or a minimum of 731 tons per day of nine hours. As three hatches are usually worked at the same time, it will be seen that from 2200 to 2500 short tons are taken out every day.
From the scales the sugar is deposited on a depressed conveyor in the floor and carried directly into the melt house of the refinery, except the sugar that must of necessity be stored in the warehouse for future use, in which case it is dumped from the trucks on piling machines that elevate it to any height desired, and it is arranged neatly and compactly by the piling crew.
The wharves and docks of a sugar refinery are, as a rule, scenes of unusual activity and interest. Besides the large number of men engaged in hoisting, trucking, weighing, sampling and piling the sugar, there are the sailors, whose calling always possesses a certain fascination for the landsman. A motley crew they are, bronzed by wind and sun, gathered from all countries and climes. There is the simple, kindly native of Hawaii, gentle-eyed, soft of speech and born with a love for the sea; he prides himself upon his skill in swimming and diving, and when the day’s work is done, entertains his shipmates by singing the plaintive melodies of his native land, accompanying himself on the ukulele, the stringed instrument of the South Seas. Should there be a number of his fellow islanders among the crew, the evening’s program is almost certain to be varied by the native hula hula dance, which generally brings marked applause from the onlookers. Presiding over the galley, or ship’s kitchen, is the almond-eyed Chinaman, now shorn of his queue; an excellent cook who loves to gamble after his pots and pans are washed and put away in place; a shrewd gamester, but scrupulously honest. Beside him stands a fierce-looking Malay, sullen, morose and taciturn, whose sharp, white teeth carry a sinister suggestion of the good old days of cannibalism. His neighbor is a Filipino, short in stature, keen-eyed and alert, while in the background are one or two individuals who from their appearance might be direct descendants of the buccaneers who ravaged the Spanish Main in Sir Henry Morgan’s time.
The average sailor is fond of pets, and here there is no lack of them, parrots and monkeys for the most part, and the sayings of the former clearly indicate a total absence of Sunday-school training.
Sugar ships bring rare fruits and vegetables from the tropics, and the employés of the refinery have plenty of opportunities to enjoy such luxuries as fresh pineapples, bananas, guavas, papaias, alligator pears, breadfruit and mangoes.
A visit to the docks of a sugar refinery during the time vessels from foreign ports are lying there is well worth while, although in these days of steam, the picturesque features are not so pronounced as they were before the passing of the sailing vessel.
WASHING
REMOVAL OF SUPERFICIAL IMPURITIES
As a starting point in the refining process the melt house will be first considered. It is so called because it is there that the raw sugar enters the refining process by being melted or dissolved in water.
The conveyor, upon which the bags were deposited in the warehouse, delivers them on a platform on the top floor of the building. As they come to this platform from the conveyor, workmen with keen-edged knives seize them and, with a deft, swift slash, cut the twine sewing at the top of the bag without injuring the burlap fabric. The bag is then pulled off the platform, mouth downward, so that the sugar falls out and passes through an iron grating into a large bin beneath. If the sugar should happen to be caked or lumpy, it is sent through crushers and broken up.
As a certain amount of sugar adheres to the inside of the bags, they are washed in large revolving machines and in this operation the sugar dissolves in the water (called sweet water), from which it is extracted later. They are then partially dried in centrifugal machines and hung on hooks on a traveling chain conveyor that passes through the upper part of the boiler house, where the waste heat thoroughly dries them. In returning, the conveyor passes through the bag room and, by means of an automatic device, the bags are dropped alongside the printing presses. Here the name of the refinery, the kind of sugar and the net weight they are to contain are printed upon them. These burlap bags are then lined with a white cotton bag, after which they are made into bundles and sent to the packing room to be filled with sugar. It will be seen, therefore, that the bags from Hawaii in which the raw sugar is received are put to good use. This, however, does not apply to those that come from Cuba or Java; they are too large to serve as containers for the refined product, and after being washed and dried are sold for what they will bring.
The white cotton bags are made at the refinery, and a plant turning out one thousand tons of sugar each twenty-four hours will use twenty-five thousand yards of cotton sheeting per day if all the output is packed in one-hundred-pound bags.
The bin into which the raw sugar is dumped holds enough sugar to keep the refinery supplied during the twenty-four hours run, but the entire quantity is “cut in” during the day. The advantages of this arrangement are that it avoids any delay in operation due to mechanical troubles with conveyors and because more efficient work is accomplished during the daylight hours. The employés prefer to work on the day shift and, wherever possible, night work is avoided.
From the bottom of the bin the sugar falls into a mixing machine, called the mingler. This is an oblong tank with a semi-cylindrical bottom, near which is a revolving horizontal shaft, with arms or paddles attached which thoroughly stir and mix the sugar with syrup that is added at this point. The reason for using syrup instead of water is that the former, being a saturated sugar solution, does not melt the sugar as water would.
The resultant mixture, called magma, looks a good deal like a soft, brown mortar. It is, in fact, raw-sugar crystals swimming in syrup. This consistency is needed to allow the magma to work freely in the centrifugals, the next operation. Most of the impurities contained in raw sugar are superficial, that is, adhering to the outside of the grain. They may be more or less readily removed by washing the surfaces of the crystals with water.
From the mingler the magma drops to the floor below into centrifugal machines running at the rate of 1100 revolutions per minute. A “charge” consists of about nine hundred pounds of magma. As the machine fills, the centrifugal force causes the magma to rise in a vertical wall around the inside circumference of the basket, at the same time throwing off the syrup that was added on the floor above, and leaving in the machine about five hundred pounds of the raw sugar as it came from the plantation. Water is then sprayed into the machine under high pressure, through a nozzle which divides it into very fine particles and throws it against the wall of sugar in the machine. The water, passing through the sugar by the centrifugal force, washes each face of each crystal and carries off the impurities, together with a certain amount of sugar. The quantity of water used per machine in each filling is from one to two and a half gallons, depending upon the quality of the sugar.
This water, now a syrup, with the impurities and sugar it contains, is drawn from the machine, part of it being pumped to the floor above to mix with new raw sugar coming in. The remainder is treated, filtered, boiled and made into raw sugar, which, in turn, goes direct to the melt or through the washing process again. The result of this washing is that the purity of Hawaiian raw sugar is raised from about 97.2 to 99.2 per cent, and there now remains but 0.8 per cent of impurities to be removed.
The washed sugar is dropped from the centrifugal basket through a large opening in the bottom of the machine with the aid of a mechanical device called a discharger, which greatly reduces the manual labor.
Until very recently the sugar was discharged from the centrifugals by hand, the men digging it out with wooden paddles in a difficult, laborious way. One day, a few years ago, a clear-brained, observant American lad working in a beet-sugar factory, conceived the idea that a centrifugal could be emptied by mechanical means. He worked long and assiduously upon the problem, and after much experimenting and many trials and disappointments was granted a patent by the United States government. Full of hope and confidence, he had several machines constructed and took them to a sugar refiner, sure of being favorably received. He met with rebuff and ridicule. The refinery engineer was too busy with other matters to examine or give any attention to the appliance. The next man to whom he presented it was even more indifferent than the first; he coldly informed the patentee that he had been in the sugar business for thirty years, that no such machine would work, and that the only way to take sugar out of a centrifugal was by hand.
After months of effort and repeated failures, he induced the superintendent of a beet-sugar factory to allow him to install and test the device at his own expense. It was thrown out after a few days’ trial, and the inventor became well-nigh desperate, although still positive as to the merits of his discharger.
Finally he succeeded in gaining the ear of the manager of a large refinery, who, after listening attentively to his earnest argument, at length became convinced by it. As a result of the interview, it was arranged between them that the machines rejected by the beet-sugar factory should be installed in the refinery and operated for a period of thirty days, under the direct supervision of the inventor. The test was successful in every particular and conclusively proved the efficiency of the discharger.
The refiner was gratified because on account of the saving in time the capacity of the centrifugals was materially increased; the men operating the centrifugals were hugely pleased, as the arduous work of emptying by hand was entirely eliminated, and the inventor was happy, for he had vindicated himself.
An order for a large number of the machines was placed at once and every centrifugal in the refinery was equipped with one. Today they are installed in nearly every refinery and factory in the United States, and in many raw-sugar plantation mills as well.
MELTING
CHANGING THE SOLID RAW SUGAR INTO LIQUID FORM
From the centrifugals the washed sugar drops to the melter pan on the floor below. This is a cylindrical tank in the center of which is a revolving vertical shaft, to which are attached horizontal paddles that serve to facilitate the dissolving of the sugar with the hot water that is now added. Only enough water is added to bring the resultant liquor to a density of 58.6 per cent of solid matter.
The raw sugar having been washed and, to use a technical term, _melted_, leaves the melt house at this point.
DEFECATION
PRECIPITATION OF SUSPENDED AND INSOLUBLE IMPURITIES
From the “melt” the liquor is pumped to the top floor of the char house, which is usually a structure of from twelve to fourteen stories high. The reason for building to such a height is the advantage gained by utilizing the force of gravity and by this means handling the liquors and bone-char from floor to floor without mechanical aid.
The liquor is delivered into a number of cylindrical tanks equipped with a coil of pipe through which steam is passed for heating the liquor, each tank being capable of holding 25,000 pounds of liquor. Around the bottoms of the tanks are perforated pipes through which compressed air is forced to agitate and thoroughly mix the solution. On account of this air being blown in, these tanks are called blow-ups. By means of the steam coil the temperature of the liquor is kept at 190 degrees, which makes it less viscous than cold liquor, thus facilitating subsequent filtration and hastening the reaction of the lime and acid added at this point.
As the liquor comes into the blow-ups it varies in color from a straw yellow to a dark brown, and contains a considerable amount of suspended and insoluble impurities which must be removed. Some of these impurities are present in the raw sugar, and others, such as pieces of twine, lint from the bags, fine particles of leaves from the Java baskets and Philippine mats, are traceable to the opening of the containers in the melt house.
The process of removal is called defecation. In former years this was accomplished by adding bullocks’ blood to the raw-sugar liquor in the blow-ups and heating the mixture until the scum which rose to the surface cracked, when the solution below was found perfectly clear, or, in the language of the refinery man, _bright_. Today, however, chemicals are the defecating agents, those most commonly used being phosphoric acid and lime. Phosphoric acid, neutralized with lime, throws down a heavy, flocculent precipitate which, as it settles, sweeps the solution and drags down all the suspended matter, gums, etc., leaving the liquor above clear and transparent.
The precipitate must now be removed, and this is accomplished by running the liquor through the bag filters on the floor below. These filters are tight iron boxes, about sixteen feet long, six feet wide and seven feet high. The top of the box is depressed about eight inches below the sides and ends, thus forming a tank. This top is perforated with five hundred holes, one and one-half inches in diameter. From the bottom of the iron box is an outlet pipe leading into tanks below.
In each of the holes on the inside top of the box is screwed a so-called “brass bottle,” conical in shape, to which is securely attached a closely-woven cotton filter bag, about twenty-four inches wide and seventy inches long. This filter bag is encased in a heavier and stronger cotton sheath, or sleeve, about eight inches wide, which adds strength and keeps the twenty-four-inch bag in folds so as to give an effect similar to that of a folded paper filter, frequently seen in drug stores. Each bag filter contains five hundred of these bags, suspended vertically from the top.
Before any liquor is run on the filters, the bags and the iron box are heated by means of steam to bring the apparatus to a temperature of about 190 degrees Fahrenheit. This prevents the chilling of the sugar liquor by cold bags, which would cause the bags to become “blocked,” as it is technically called. The liquor from the blow-ups, at 190 degrees temperature, is now turned into the depressed tank on the top of the filter and flows through the perforations into the bags attached on the inside, down through the bags, and finds an exit through the bottom of the filter into the tanks below.
As the first liquor comes through the bags, it is a little cloudy, but in a few minutes, as the pores of the bags fill with the insoluble substances, it becomes perfectly bright, all the suspended and insoluble impurities remaining in the bags, together with the precipitates drawn over from the blow-ups. The cloudy liquor is pumped to the top of the filter and clarified by being run through a second time. It is interesting to know that it is not really the bag that does the filtering, but the thin layer of sediment that is deposited from the liquor itself on the inner surface of the bag. The cotton bags are made in a particular manner, and from a fabric especially adapted to catch the sediment and to form, in conjunction with it, an excellent filtering medium.
The liquor, as it runs into the tanks, must be carefully watched, for sometimes a bag inside the filter breaks, which causes cloudy liquor by allowing the precipitates to gain entrance into the clear liquor. As soon as this is noticed, samples are taken from the outlet of each filter and the defective one found and investigated.
When a bag is torn, or develops a hole, the liquor runs through the opening on the top of the filter so fast that it forms a little whirlpool, which shows the bag that is broken. A wooden plug is immediately driven into the opening and that particular bag cut out. The men on the bag filters soon become so expert that they detect broken bags and plug them before the cloudy liquor gets to the inspection station. It is essential that the liquor be freed from all suspended impurities at this station before the next step is taken, hence great care and watchfulness must be exercised.
In time the coating of sediment, gums and precipitates on the inside of the bag becomes so thick that the liquor runs very slowly and finally stops. The refinery term for this condition is “stuck-up.” Depending on the impurities in the original liquor, the bag filters will continue to filter the liquor for from twelve to twenty hours and sometimes longer.
After the bags are “stuck-up,” the liquor remaining in them is sucked out by means of vacuum through a small pipe attached to a long rubber hose and inserted in the bags through the holes in the top of the filter. The liquor thus sucked out of the “stuck-up” bags is sent to the blow-ups and reprocessed with new liquor, thus beginning its journey anew.
As soon as the liquor is sucked out, hot water is run through to reduce the sugar contents of the filter. This water is saved and the sugar it takes up is subsequently recovered. The filter is then opened by means of an electric hoist traveling on an overhead track immediately above the filters. Chains are attached to the top of the filter and the hoist elevates top, bags and all, to a point sufficiently high for the bags attached to the top to clear the adjoining filters. The top and bags are then moved along the track to the washing station. Meanwhile another hoist has delivered a duplicate top, with fresh bags attached, to the filter, where it is lowered into place. In this way the filter is again in operation within five minutes. At the washing station the bags just taken from the filter are detached from the top for washing, and the top is sent to a point where clean bags are again attached. It is then ready to go into another filter.
At the washing station the dirty bags are pulled out of the sheaths and turned inside out in tanks containing water, thus releasing a large quantity of the impurities. The bags and sheaths are then thrown into washing machines, where all the remaining impurities and sugar are washed out of them. From the washers the bags are put into centrifugal machines, or through powerful wringers, and dried sufficiently to permit being rehandled. They are then resheathed and made ready to be attached to another top.
The water from the washers contains a large amount of sugar and is conducted to a tank similar to one of the blow-ups, where it is treated with lime and diluted with water at 190 degrees Fahrenheit until it contains only from ten to twelve per cent of solid matter. This liquid is then pumped through filter presses and the impurities removed. The “sweet water,” as it is termed, which now contains practically all the sugar, is collected in tanks and the sugar is ultimately extracted by evaporation, filtration and boiling to grain.
The impurities removed by the filter presses consist of sand, portions of bags and baskets, phosphates, hair, lime, salts and gums, in fact every kind of foreign matter that finds its way into raw sugar either in the process of manufacture or in transportation. A small amount of sugar accompanies this refuse, but as its recovery would cost more than it is worth, it is allowed to run to waste. The filter-press cake, as it is called, contains valuable fertilizing agents, and when conditions permit it is used for fertilizing purposes, otherwise it is run to waste.
BONE-CHAR FILTRATION
REMOVAL OF COLOR
To resume the course of the bag-filtered liquor, from which the superficial, the suspended and insoluble impurities have been removed and which is now the color of clear amber, the next step is bone-char filtration.
Bone-char, bone-coal or bone-black, as it is variously called, is made from the bones of animals. After the fat and glue are removed, the bones are subjected to a dry distillation which carbonizes them. These charred bones are then broken into very small pieces, or until they will pass through a ten-mesh screen and remain on a thirty-mesh screen; in other words, the size of the grains used in a sugar refinery vary from one-tenth to one-thirtieth of an inch. If properly manufactured, the grains are hard, porous, and have a great affinity for moisture.
Bone-char has the peculiar property of removing from the sugar liquor, in some unknown mechanical way, not only the soluble salts but the coloring matter as well. The elimination of the salts and coloring matter facilitates the subsequent crystallization.
The char house is, therefore, by far the most important station in a refinery, for failure in the char house means failure throughout.
Contrary to the general practice in Europe, beet-sugar factories in the United States do not use bone-char, and consequently do not take all the coloring matter and salts out of the liquor. They secure a white sugar by other methods, which will be explained later on. In a cane-sugar refinery, however, the coloring matter and impurities are entirely eliminated, and the product is invariably pure and white.
The char filters are cast-iron cylinders, usually ten feet in diameter and twenty feet high, with doors at the top for entrance of the char and openings at the bottom through which it is removed. There are also many pipe connections for the introduction and outlet of liquors, steam, hot water and compressed air. The filters are insulated on the outside with asbestos or some other non-conductor of heat to prevent the temperature of the liquor from being lowered as it passes through. Each filter has a capacity of from sixty thousand to eighty thousand pounds of bone-char.
At the bottom of the filter is a perforated iron plate. Over this is placed a coarsely woven cotton blanket, through which the liquor will pass, but which prevents the char from escaping from the filter with the liquor or wash water. After the blanket is set in place, the char is delivered by gravity through an overhead pipe into the filter, until it is entirely full. The char, as it goes in, has a temperature of from 170 to 180 degrees Fahrenheit, and the bag-filtered liquor which is then run on has a slightly higher temperature.
When the liquor in the filter reaches the top and the char has settled in a compact mass, the cover is put on and fastened securely to prevent leakage. The liquor is again allowed to run into the filter by gravity, from the tanks about fifteen feet overhead. The valve on the bottom of the filter is then opened and the liquor, as it filters slowly through the char, is led through a copper pipe to the liquor gallery, to which station all the char-filtered liquor is delivered. This pipe, instead of leading downward from the filter, leads upward and nearly to the top, so that the flow of liquor through the char will be slow and uniform and the filter will always remain full of liquor. The diameter of the filter is ten feet, while that of the outlet pipe is two inches, so that the flow of liquor through the char is necessarily very slow. The reason for this is that the liquor must remain in contact with char a certain time to enable the char to absorb the coloring matter and soluble salts.
The first liquor from the filter appears cloudy and is sent back for refiltration, but it soon becomes bright, perfectly colorless and transparent as plate glass. This white liquor is pumped from the liquor gallery into the tanks on the top floor in the pan house, ready for the next process, which will be dealt with presently.
After a filter has been running for from twenty-four to thirty-six hours, depending on the character of the sugar in the liquor, the char becomes “tired” or spent. In other words, it has absorbed so much of the impurities and coloring matter from the liquor passing through it that its capacity to absorb more is gone and the liquor begins to show a slight straw or canary color. The inspector in the liquor gallery immediately notices this and orders the liquor stopped. Immediately afterwards a lower-grade liquor is turned into the filter, which forces the first liquor out before it. In due time the man at the liquor gallery notices the number two liquor coming from the filter and turns it into separate tanks. In time a still lower grade of liquor is turned on and the filter run until the bone-char is absolutely exhausted, when it is ordered “sweetened off.”
Hot water is then turned in at the top of the filter to wash out the remaining sugar liquor which gradually becomes more and more dilute. When its density has been lowered to about thirty-five per cent of solid matter, it is diverted to other tanks, and this is continued until only three-tenths of one per cent of sugar remains in the sweet water, as it is now called. The washing of the char in the filter in this manner, by hot water, is kept up for twelve hours, but as soon as the sugar content falls below three-tenths of one per cent the solution is allowed to run to waste, as the recovery of this small percentage of sugar would cost more than its value.
The sweet water is sent to the evaporators, concentrated to 58.6 per cent of solid matter, and it then begins its refining journey over again.
This long and continued washing of the filters is for the purpose of removing as much as possible of the organic and mineral impurities absorbed by the char.
The washing completed, compressed air is applied to the filter to force out the remaining water. The bottom doors of the filter are then opened and the char, containing about twenty per cent of water, drops to the floor below. Here it passes through mechanical driers and is delivered comparatively free from moisture to the kilns. There it is revivified, that is, the organic matter in the char which could not be removed by washing is converted into carbon by being heated to a cherry red in the absence of air. This is accomplished by allowing the char to pass by gravity through the red-hot retorts of the kilns.
As the wet char leaves the filter, it drops on a moving belt which carries it to large cast-iron hoppers leading to the driers immediately beneath, where the greater part of the moisture is expelled from the char prior to its being treated in the revivifying kilns. The driers are made up of a number of thin, hollow, cast-iron, triangular pipes, enclosed in a large, rectangular, outside casing. The wet bone-char passes over these hollow pipes as it falls slowly through the drier. The hot gases from the furnaces of the kilns below pass through these cast-iron pipes, giving off heat as they ascend, thus driving off the moisture in the char as it falls down over the outer surface of the pipes. At the same time, hot air obtained from cooling the char in the cooling pipes below the retorts is drawn through the drier, coming in direct contact with the char. The moisture given off by the char is absorbed by this hot air and carried out of the drier and building by fans or smokestacks. By this means the water in the char is reduced to ten per cent, and in this comparatively dry, hot state it runs freely by gravity from the bottom of the drier into a second set of hoppers, through which it drops into the retorts of the kiln. The hot gases, after drying the char, pass out at the top of the drier through a flue leading to a stack outside the building.
The kilns are large square boxes of brick, built around a strong supporting iron structure. On each side of these boxes are a number of large flat pipes of cast iron, nine feet long and twelve inches by three inches in section, the iron being three-quarters of an inch thick. These pipes are called retorts and are arranged vertically in the kilns, forty on each side. The space in the center between the retorts is known as the furnace and extends the entire length of the kiln, a distance of about sixteen feet. Intense fires are maintained in this central space and the flames playing around the retorts keep them red-hot. The upper ends of the retorts lead into the hoppers above and the lower ends to the cooling pipes below. As the char passes gradually through the red-hot retorts, it becomes heated to 900 degrees Fahrenheit and the organic matter it absorbed from the sugar liquor is changed into carbon. In this way the char becomes almost as good as new, or, as the term goes, revivified. Each kiln has a capacity of revivifying sixty thousand pounds of bone-char per day.
If the char in this red-hot state were suddenly exposed to the air, the contact with oxygen would bring about combustion and the char would be quickly reduced to ashes, so a cooling process is necessary. It is, therefore, drawn from the cast-iron retorts into cooling pipes located directly beneath. These pipes are of thin sheet-iron and are about three by four and a half inches in section. There are three under each retort, and a mechanical device at the bottom allows only a small amount of char to escape at a time. This amount can be regulated at will by the operator, and in this way the char is held in the retorts the exact time necessary for its revivification.
A current of cold air circulates continually around the cooling pipes, taking up the heat from the char and delivering it through pipes to the drier overhead, so that when the char leaves the bottom of the pipes its temperature is about 180 degrees Fahrenheit. From the cooling pipes, it drops on a belt conveyor from which it is carried by endless belt or chain bucket elevators to the top of the char filters to be used again.
The manipulation of the char filters varies in different refineries, some running the liquor over the char for a longer period than others, but a fair average of the time required for filling, settling running liquors and syrups, sweetening off, washing, applying air and emptying, is eighty-six hours, the shortest time being seventy-two hours. Taking eighty-six hours as a basis, it will be seen that the char is handled and revivified eighty-one times each year after making due allowance for Sundays, holidays and annual clean-up periods.
Each time the char is handled, a certain amount of it is broken into dust, and this is taken out by passing it over fine screens, and also by exhaust fans. Obviously, the amount of dust taken out each day must be replaced by its equivalent in new char. It is estimated that the original char put into the filters will last from five to six years before it finally becomes disintegrated and is taken out as dust.
As approximately one pound of char is required for every pound of sugar melted, it will be seen that as the liquor is in contact with the char for only twenty-four hours out of seventy-two, a refinery turning out two million pounds of sugar per day should have filter capacity for six million pounds of char. The amount of the latter that is handled each year is, therefore, very great and requires a large and costly plant to take care of it properly.
CRYSTALLIZATION
PRODUCTION OF CRYSTALS BY CONCENTRATION
The refining process has been described up to and including the purification and decolorizing of the sugar liquor, the last step being the delivery of the pure white liquor into the receiving tanks in the pan house.
After the white liquor leaves the char filters, the greatest care must be exercised to keep all the machinery, piping and apparatus scrupulously clean, for if any foreign matter becomes mixed with the liquor or sugar it can only be removed by refiltering or remelting.
By means of vacuum, the liquor is drawn from the tanks into the vacuum pans, this being the last operation in which the sugar is handled in a liquid state. From this point on it drops by gravity from floor to floor in a solid or semi-solid form, until it reaches the packing room as a finished product. In a first-class refinery, the vacuum pans, as well as all the piping through which the liquor passes, are made of copper instead of iron and steel, which eliminates the possibility of rust or scale getting into the sugar.
Refinery vacuum pans are usually from fourteen to sixteen feet in diameter and from sixteen to seventeen feet high, while in shape they appear almost spherical. The boiling takes from one hour and twenty-five minutes to one hour and forty-five minutes, and about forty-five tons of granulated sugar can be made at each boiling in a fourteen-foot pan. Before the liquor is drawn in, the pan is thoroughly cleansed with hot water and steam. All openings are then closed and the vacuum pump started. The air is quickly exhausted, a valve in the pipe line leading from the receiving tank is opened and the pan is given a charge of liquor. Steam is turned into the coils of the pan and the boiling process begins. Soon sufficient moisture is driven off to cause the sugar to “grain.” Shortly after the grain forms, another charge of liquor is drawn into the pan and the operation is repeated until the pan is full of a thick, white, mushy substance called massecuite, that looks very much like half-formed ice. The vapor driven off in the boiling passes out through a large pipe at the top of the pan and is condensed by being sprayed with cold water. On account of the high vacuum, the liquor boils violently at temperatures ranging from 140 degrees to 195 degrees Fahrenheit; thus the risk of scorching, discoloration or caramelization of the sugar is minimized.
On the front of the pan is a vertical row of windows made of heavy plate-glass, and through these the liquor is watched during the boiling. The massecuite in the pan is sampled at intervals by the sugar boiler, by means of a “proof stick,” a brass rod about three feet long and one and one-quarter inches in diameter, in the pan end of which there is a hollow space. This stick is pushed through an opening in the side of the pan into which it fits tightly, and then partly withdrawn. A small quantity of the contents of the pan remains in the hollow space, and this the sugar boiler removes and places on a piece of clear glass. On holding it up to the light, he sees exactly how the crystallization of the sugar is progressing, and by observing and feeling the crystals, he is enabled to control the boiling perfectly. When he concludes that the evaporation is complete and the massecuite of the proper consistency, the pump is stopped and the vacuum broken by opening a valve near the top of the pan, admitting the outside air. The foot valve is then opened and the massecuite drops from the pan into a mixer directly underneath. There it is kept constantly in motion by a revolving shaft with paddles, to prevent the crystals from sinking to the bottom. From the mixer it is drawn into the centrifugals and purged of the mother liquor, the pure crystals being left in the machine. The liquor thus drawn off contains whatever impurities may have remained in the original liquor. It is now pumped back and run through the char filters again, after which it is boiled in the vacuum pan and the granulated sugar taken out in the centrifugals. This completes the process of producing crystallized sugar by concentration.
There are many interesting and intricate problems in connection with the extraction of the sugar from the wash waters, sweet waters and low-grade syrups that are constantly accumulating in a sugar refinery, but space will not admit of their being dealt with here. Suffice it to say that the process of extraction is carried to a point where the sugar recovered barely pays for the labor and fuel expended in the operation. The ultimate result is white sugar, table syrup and molasses.
This molasses is used largely in the manufacture of vinegar and alcohol. Mixed with grain and alfalfa meal, it makes an excellent stock food that cattle take to readily and that possesses high value as a fattening agent. The sucrose and glucose content of molasses as it leaves the refinery is about fifty per cent.
Naturally, in a process involving so much handling, filtering and boiling, there must be some loss, and the efficiency of a refinery is based upon the percentage of granulated sugar recovered from the raw article delivered to the melt. It may be stated for general guidance that, taking an average of the refineries of the United States, one hundred pounds of refined white sugar is made from each one hundred and seven pounds of ninety-six-degree raw sugar melted. Some of the sugar lost is accounted for in the molasses, in the sediment from the filter presses, and in the wash waters from the char filters. The remainder is the undetermined loss in handling, in sugar destroyed by heating, and in sugar dust escaping during the manufacturing operation. As has been said, the component parts of raw sugars vary more or less, and the recovery in white sugar from two lots of raws, each polarizing ninety-six degrees, might differ considerably according to the refractory matter in the original raw sugar.
The following figures give a fairly accurate idea of the disposition of one hundred pounds of ninety-six-degree raw sugar in refining:
Water, which is eliminated .70 per cent Non-sugar, which is eliminated 3.30 ” Sucrose loss, undetermined .75 ” Sucrose left in molasses 1.75 ” Sucrose extracted in granulated form 93.50 ” ------ Raw sugar melted 100.00 ”
The undetermined loss includes every loss from the time the raw sugar is weighed into the warehouse until the granulated article is sold to the buyer. It is evident, therefore, that one of the principal items of refining cost is the actual loss of weight in converting raw into refined sugar. Assuming that the raw sugar costs four cents per pound, the refiner has lost on each one hundred pounds melted, four cents × 6½ pounds, or twenty-six cents, less the small value of the resulting molasses. If the raw sugar cost six cents, the loss would be thirty-nine cents. At four cents, the loss is equivalent to $5.20 per ton, or, in the case of a refinery melting two million pounds of raw sugar daily, $5,200.00 for each working day. This does not include any of the operating expenses, such as labor, fuel, bone-char, containers, selling expense or administration—just the actual value of the raw sugar lost in the process of refining.
PARTIAL DRYING
PURGING CRYSTALS FROM THE SYRUP
Returning to the sugar left in the centrifugals, the force developed in a machine forty inches in diameter, spinning at the rate of eleven hundred revolutions per minute, is so great that it quickly dispels all the liquor surrounding the crystals, leaving them nearly dry, in a solid, vertical wall. Water, filtered to insure its purity and cleanliness, is then sprayed on this spinning wall of sugar, only to be immediately thrown off through the sugar by the centrifugal motion. In passing through the sugar it washes the last of the syrup from the grains and leaves them perfectly white. Cold water, rather than hot, is used for this purpose, as it dissolves less sugar.
In former years a small quantity of bluing was added to the spraying water in order to enhance the whiteness of the sugar, just as bluing is employed in washing fine linen fabrics. Since the pure-food laws became effective, however, the practice has been discontinued in all cane-sugar refineries.
After the sugar is thoroughly washed, the centrifugal machine is stopped, a large valve in the bottom opened and the mechanical discharger rapidly ejects the sugar (now containing only about 1.2 per cent moisture) from the machine into a storage bin beneath.
FINAL DRYING OF CRYSTALS
For some reason not well understood, the next step in refining is called “granulation.” Actual granulation, or crystallization, takes place in the pans, and the process about to be described should properly be called drying. The manufacturing term, however, is as given.
Drying is effected in an apparatus consisting of two large cylindrical drums of wrought iron. These drums are about six feet in diameter, thirty feet long and have a slight downward pitch from the receiving to the discharging end. The first drum rests on the floor, directly below the storage bin, and is called the sweater. It turns slowly on revolving wheels, by means of circular tracks bolted to it. The power that moves it is delivered from an electric motor, through a pulley, shaft and pinion, the latter working in a gear bolted to the outside circumference of the drum. Fastened to the inner surface of this drum is a series of short, narrow shelves with saw-tooth edges that serve to carry the sugar to the top of the revolving cylinder, whence it falls to the lower side, causing a continual shower of sugar throughout the entire length and breadth of the drum. The sugar is delivered through a pipe at the upper end of the sweater, and the revolving motion together with the incline of the cylinder gradually works it down to the lower end. Here it drops through a chute to the granulator on the floor below, where the process of drying is completed.
A strong current of hot air is drawn through the sweater by a powerful fan connected to the upper end by a very large pipe. The air introduced in this way is brought to a high temperature by passing around a number of coils of pipe charged with steam, which are placed directly in front of the sweater. The hot air sweeping through the drum absorbs nearly all of the moisture in the sugar, which carries 1.2 per cent of water when it enters the drum and about 0.1 per cent as it leaves it.
The granulator, or lower drum, is the same size as the sweater and is constructed in very much the same manner, having shelves for carrying the sugar to the top and dropping it at the proper point, and being equipped with a large fan to draw off the hot, moist air. Instead of having steam coils in front, however, it has in its center a steam-heated drum about twenty-four inches in diameter that revolves with it. The sugar crystals, as they fall in a shower from the shelves, come in contact with the hot inner drum on their way through the granulator, and in this manner become thoroughly dried. The moisture in the sugar, as it emerges from the granulator, is less than four-hundredths of one per cent, an amount too slight to determine except with the most delicate apparatus.
To insure perfect drying, the damp sugar must be fed to the upper drum or sweater with unfailing regularity. This is accomplished by the use of revolving screws located under the storage bins. By turning a certain number of revolutions per minute, they deliver an even and steady supply of sugar.
From the granulators the sugar is dropped on thin cotton belts that, passing around highly magnetized pulleys, carry it to the dry storage bins. The sugar is cooled to normal temperature before being packed in containers, thus preventing subsequent absorption of moisture and consequent caking.
Magnetic pulleys are used to extract any particles of iron scale or rust that may drop into the sugar after the liquor leaves the char filters. Rust sometimes forms in the pans, mixers, conveyors, elevators, sweaters or granulators, and should it get into the sugar the magnetic pulleys will surely remove it.
Storage bins and storage tanks are prominent accessories of all sugar refineries, for if a breakdown should occur at any point, there must always be a supply of material on hand to keep the refining operations going while the trouble is being remedied.
SCREENING
SEPARATING CRYSTALS INTO VARIOUS SIZES
The now thoroughly cold, dry and free-running granulated sugar is drawn from the storage bins through galvanized metal pipes and taken to the separators by screw conveyors, which deliver it at an even, steady feed—a most essential feature. The sugar as it comes from the pans is made up of crystals of various sizes. It also contains a number of small lumps formed in the centrifugal machines, or in some part of the process after it leaves the pans. It is necessary to separate the crystals according to size and to screen out the lumps, for the following reason:
In some parts of the country, people have been educated to use a coarse-grained sugar; in other sections, they are accustomed to sugar of a fine grain. For example, on the Pacific coast, the demand is for the fine-grained article; the consumers of the Mississippi river valley like a fairly large grain; while the Atlantic coast trade calls for a still coarser product. There is a difference, too, as to containers. In the East the preference is for the barrel package, while the Western buyer wants his sugar put up in bags.
There are many different types of separators commonly in use, but in all of them the governing principle is the same. It is the elimination of lumps and dust from the final product and the separation of the sugar crystals according to size. The separator here specifically referred to will explain the principle as well as any other type, and a glance at the accompanying illustration will give the reader a good idea of its construction. It is made up of a number of wire screens of various sizes, fixed at a sharp incline, one above the other, and all enclosed in a tight, dust-proof steel case. At the top of the case is a steel screw conveyor by which the sugar is fed evenly and steadily across the entire width of the top screen.
On the outside face of the case are a number of shafts to which hammers are attached. As the shafts revolve, the hammers tap the various screens below, lightly and at rapid intervals, thus causing them to vibrate.
The upper screen, called the scalper, is quite coarse and allows all the sugar to fall through except the lumps, which run down the face of the screen into a pipe that carries them to the melt, where they begin the refining process over again. These lumps, however, represent a very small proportion of the whole.
The second screen is finer than the scalper. It permits part of the sugar to pass through, but retains a certain amount which falls down on the face of the screen, whence it is led through a pipe to a special bin. Sugar of this size is known as coarse granulated.
The next screen lets the finer grains drop through, but catches the standard granulated, which in turn is drawn off to its special bin. The last screen, an extremely fine one, retains the extra fine granulated, and this in turn is delivered to its appointed bin. The sugar passing through the last screen is so fine as to be classed as “dust,” which, not being marketable, is usually remelted.
The amount of any one grade of sugar obtained from the separator may be changed, within certain limits, by the boiling in the vacuum pans. If a large proportion of fine-grained sugar is required, the sugar boilers are instructed accordingly. It is impossible, however, to boil all the grains in each strike a uniform size, or to boil any two strikes exactly alike, so the separators are necessary, especially for removing the lumps and dust. The dust is caused by the constant falling of the dry sugar crystals against each other in the driers and granulators, and by the grinding action upon the sugar crystals in the screw conveyors.
PACKING
FILLING VARIOUS KINDS AND SIZES OF CONTAINERS
When putting up his goods, a sugar refiner—like every other manufacturer—must needs cater to the wishes and tastes of the consuming buyer. The modern tendency in containers is in favor of sealed air-tight and dust-proof packages. Some refiners spend great sums of money every year in advertising the merits of special sugars packed in dust-proof cartons. Their rivals generally follow suit, as competition in the marketing of sugar is probably far keener than in any other line of business.
The plain truth is that all refined granulated cane sugar offered for sale in the markets of this country today is almost identical, irrespective of the manner in which it may be packed. The poorest quality of refined sugar made has, in all likelihood, a purity not lower than 99.5 per cent, while the highest grade cannot possibly exceed 99.9 per cent, a difference of only four-tenths of one per cent, hence it is evident that all refined sugars are practically pure, the fancy package simply meaning a fancy price.
The methods of transporting and handling the sugar after it leaves the refinery may justify the additional expense, but this is subject to argument. However, it makes but little difference to the manufacturer, as the cost of the package as well as the extra handling is always included in the selling price.
A few years ago all sugar went out in barrels or bags, while today a modern refinery turns out about twenty different styles of container, and twenty-four kinds of sugar. It is obvious, therefore, that the packing room of a refinery is an interesting place, covering as it does a large area and including a great amount of special, intricate machinery for filling, weighing and sewing or sealing packages.
In the bottom of the bins into which the sugar is delivered from the separators is a series of galvanized iron pipes, through which the sugar runs to the various filling devices, the latter being usually arranged in long rows. Under the end of each pipe is an automatic weighing machine. In packing bags, a workman hangs a bag on the weighing machine and presses a lever, thus allowing the sugar to run into the bag. As soon as the exact amount required is reached, the flow is automatically cut off. These weighing machines are so accurate that they gauge the amount to within a fraction of an ounce. The operative removes the full bag, places it on a conveyor that runs in and level with the floor and quickly adjusts an empty one on the weighing machine. These men become so expert that a single operative will fill two hundred and fifty one-hundred-pound bags per hour. The weighing machines are designed to fill and weigh four hundred and eighty one-hundred-pound bags per hour, but the operative cannot handle them at this rate.
Four sewing machines, specially designed for sewing the filled bags, are located immediately over the conveyor and in direct line with it. As the bag passes along on the conveyor, the operative at the first machine picks up the end of the inner cotton sack and passes it through his machine, stitching it securely. The bag then passes along to the third machine, where the operative takes hold of the outer burlap bag and sews it in the same manner. Each operative has a spare machine ready for instant use in case the one he is running gets out of order. Continuing its journey to the end of the conveyor, the bag is deposited on the main belt conveyor, which takes it without manual aid to the shipping floor or the storage warehouse. A sewing-machine operative will sew as many as seventeen bags per minute, but it is trying work and the men relieve each other at intervals during the day. Both the one-hundred- and the forty-eight-pound sacks are handled in this manner. Formerly the half sacks weighed fifty pounds, but since the Parcel Post law went into effect they have been changed to forty-eight pounds to permit of their shipment by mail. Those containing twenty-five, ten, five and two pounds are weighed and sewed in much the same way, by the aid of specially designed, rapid-handling machinery. The small package machines will accurately weigh and fill five-pound bags at the rate of twenty-five packages per minute, the others in proportion.
The paper boxes, or cartons as they are called, are weighed and filled by special machinery. This machinery seems to possess an intelligence almost human. One girl feeds the cartons (the tops and bottoms of which are open) into the machine at the rate of thirty-two per minute. The machine glues the bottom, weighs the sugar to within one thirty-second of an ounce, fills the carton, glues the top, seals it and passes it on to a conveyor which delivers the finished package to a table, from which it is packed into a box for shipment. Women are usually employed in putting up the lighter packages.
A short distance from the bag-weighing machines, and running parallel with them, is a line of pipes or spouts for filling barrels. On the floor under each spout is a barrel shaker. This is a heavy cast-iron plate that is lifted about one inch, first on one side, then on the other, by the action of two cams or arms attached to a revolving shaft underneath. The shaker drops back violently on the supporting frame after each lift, causing the sugar to settle compactly in the barrel as it is filled to an average weight of three hundred and fifty pounds. Naturally, the greater the amount of sugar packed in a barrel, the less the container costs per unit of output, and as the average cost of a sugar barrel in the United States is fifty cents, the container cost per one hundred pounds of sugar is 14.3 cents.
Without the shaker, not more than three hundred and thirty pounds of sugar could be put in a barrel, which would increase the cost per one hundred pounds to 15.1 cents. This difference on a single day’s output of two million pounds represents one hundred and sixty dollars, an eloquent argument in favor of the shaker.
In packing barrels, the operative first lines the barrel with heavy paper to prevent the sugar from coming in contact with the rough wooden sides and to keep it from sifting out between the staves. The barrel, thus lined, is placed on the shaker, a valve on the spout opened and the shaking barrel filled to the top. The barrel is then removed and turned over to the cooper, who heads it up and rolls it on the scale for weighing.
Before an empty barrel reaches the packing room, it is weighed and the weight (generally from nineteen to twenty-five pounds) is stamped on its side. The gross weight of the filled barrel is determined by the packing-room scales. The weight of the empty barrel is deducted and the net weight of the sugar stenciled on the head. The full barrel is then sent down a chute to the waiting freight car or to the dock for steamer shipment, or to a conveyor that automatically delivers it to the storage warehouse.
In addition to the bags, barrels, half barrels, cartons and boxes, tins of various sizes are used for the different sugars. All of these are filled and weighed automatically, and taken from the packing room by conveyors. Some of the boxes are lined with paper and some with cotton cloth; some are nailed up in the ordinary way, and others are strapped with iron at each end. As a rule, the individual tins are cased with wood, but sometimes there are a number of tins in a case. Cartons contain two pounds, three pounds or five pounds of sugar. They are packed in fiber cases holding thirty twos, twenty threes or twelve fives and also in wooden cases which hold sixty twos, forty threes or twenty-four fives each. The style of package depends upon the demand of the trade catered to.
At this point a word or two about some of the specialties, such as cube, powdered and bar sugars, as well as yellow or soft sugars, may be of interest.
CUBE SUGAR
The sugar from which the cubes are made is of a rather fine grain, boiled in special pans from liquor that has been filtered over the char at least twice. From the centrifugals under the pan it falls into a hopper in which there is a revolving screw. Directly over the screw is a tank containing a warm, white sugar liquor, very sticky and viscous by reason of its density. A pipe leads from the bottom of this tank to a point over the screw, and the liquor, which is controlled by a valve, is allowed to drip upon the sugar. The action of the screw causes the sugar and the liquor to become thoroughly mixed and feeds the damp mass thus formed into a spout leading to the cube press, the machine in which cube sugar is made.
At the top of this machine is another hopper, into which the damp sugar drops from the spout overhead, and revolving in the last-mentioned hopper are a number of small shafts with brass pegs inserted at certain intervals along the length of the shafts, like spokes in the hub of a wheel. These pegs are like human fingers in their action and they press the sugar down into the pockets of a large revolving drum placed directly under the hopper. Each pocket is the size of a cube or half cube. Working in these pockets are plungers, which fall back as the revolving drum reaches the highest point directly under the mechanical fingers in the hopper. The fingers fill the open pockets and, as the drum turns, the plungers, at a certain point in its circumference where a heavy bronze bar is placed across its face, slowly enter the pockets and in so doing compress the sugar into cube form.
Two belts run through the machine under the cylinder, carrying galvanized iron plates about twenty-four inches wide, or the same width as the cylinder, and thirty inches long. As the line of pockets into which the sugar has been pressed reaches the lowest point on the circumference of the drum, the plungers drop down, forcing the pressed cubes out of the pockets onto the galvanized iron plates which the moving belt carries along out of the way of the next lot coming from the cylinder. Each plate, as it leaves the cube press, contains five hundred and four cubes and one hundred and sixty-eight half cubes, and the time required to fill a plate is between six and seven seconds.
The belts carry the plates to a series of ovens, or driers, so placed that a large number of plates with their contents may be inserted through a door on the belt side. When the ovens are filled with plates holding the soft, moist cubes, a current of hot air is turned on at the top of the ovens, passing out at the bottom. The hot air circulating in this manner dries the cubes and carries off the moisture. Eight hours in the ovens suffice to render the cubes thoroughly dry and hard. They are then removed through doors opposite to those through which they were put in. This arrangement prevents the men who are putting the cubes into the ovens from interfering with those taking them out, for the process is a continuous one and cubes are placed in and removed from the ovens at the same time. As the cubes are taken out of the ovens, they are deposited on a belt conveyor which delivers them into bins in the packing room, ready to be put into boxes, bags, barrels and other containers.
POWDERED AND BAR SUGAR
Powdered and bar sugars are made by grinding coarse granulated sugar into fine particles and then separating these particles by screening them through fine silk cloth. The bolting of flour is a similar process. Powdered sugar has a decided tendency to cake and become hard, and the coarse sugar from which it is ground should be particularly free from moisture. After being crushed or ground between corrugated rolls turning at high speed, the ground sugar passes into a screening or sifting device, of which there are many kinds in use, the most common being the horizontal, revolving centrifugal screen. The crushed sugar goes in at the head end, and, as it enters, a number of revolving arms throw it against a silk screen on a circular frame, revolving in an opposite direction, that permits the finest, or powdered, sugar to pass through a silk cloth having over sixteen thousand openings per square inch.
The powdered sugar extracted, the remainder drops into another screen where a similar sifting action takes place, the silk of the second screen being coarser than that of the first, and bar sugar is the result. Such grains as are too large to pass through the bar screen are carried back to the rolls and reground. The bar screen has about five thousand openings per square inch.
Bar sugar, as the name implies, is generally used in preparing beverages. It dissolves almost instantly when dropped in water. Singularly enough, the average housewife is not aware of the advantages attending the use of this grade of sugar. It does not become caked as readily as powdered sugar does, and is the ideal sweetening for berries and cereals served at the breakfast meal. It is far more desirable than powdered sugar for most of the purposes for which the latter is commonly used.
It is believed by many that _all_ powdered sugar is adulterated with chalk, starch, white corn meal or similar substances. Such is not the case, and it is safe to assume that no mixing whatever is done by any refiner in America. Powdered sugar has a strong tendency to cake or become hard, and some manufacturers who buy coarse granulated sugar from the refiners for grinding purposes use starch to the extent of from two to three per cent. Chalk is never used, nor are other non-edible or deleterious substances. Starch is not introduced for the purpose of making a greater profit, but to prevent the powdered sugar from caking. The adding of starch, in all probability, increases the cost of making powdered sugar, as starch costs almost as much as sugar, and the expense of handling it and feeding it into the grinding machinery is quite an item.
YELLOW SUGARS
Yellow sugars, or “softs” as they are usually called, comprise fifteen grades, ranging in color from a creamy white to a dark brown. These sugars are used chiefly by bakers in making gingerbread, pies and cakes, although a small quantity finds its way directly into households for ordinary domestic consumption.
The characteristics of yellow sugars are that they have a small grain and contain a sufficient amount of molasses to make them moist to the touch, properties brought about by a radically different method of boiling from that applied to white sugars. They also contain a certain amount of invert sugar which preserves the softness of grain and prevents subsequent caking or hardening.
To properly explain how yellow sugars are boiled, reference must be made to the method of boiling white sugars, which may be briefly summarized as follows:
The object to be attained in boiling white sugars is the separation of the crystallizable sucrose contained in a given solution from the impurities, moisture and non-crystallizable content of that solution. The formation of sugar crystals is a natural result of the evaporation of the moisture from the liquor or solution. In order to obtain pure white crystals, it is vitally essential that, as far as possible, all impurities and non-sugars, except water, be removed from the liquor before the boiling takes place, for if the coloring matter is not thoroughly taken out, obviously the crystals will be colored. The purifying and decolorizing operation is accomplished in the char filters. After the grain is once formed in definite crystals, these crystals attract and appropriate the sucrose in solution in the process of building up their structure, while repelling or excluding the impurities, so that in consequence the latter remain in solution. Irrespective, however, of whether crystallization of sucrose takes place in solutions of high or low purity, it will only partially remove the sucrose from the solution in one operation, the limit being fixed by the amount and nature of impurities present. In order to bring about further crystallization of sucrose the solution or mother liquor surrounding the crystals must be separated from them and be again diluted, filtered and concentrated.
Briefly, the procedure in boiling white sugar in a vacuum pan is to take liquors of the highest purity for the first boiling. After the first crystals have been removed from the mother liquor in the centrifugal machines, the liquor is again diluted, decolorized by bone-char and boiled to grain. This operation is continued a number of times, the purity of the liquor decreasing each time. Finally, when the purity of the liquor falls to a certain point, the boiling is discontinued, for at this point conditions do not admit of further formation of pure sucrose crystals, and, if the process were pursued further, the resulting sugar would not be white. Therefore, when this state is reached, these low-grade liquors are boiled into a semi-refined sugar, commonly called “refinery raw,” which corresponds fairly closely in test with the original raw sugar, or they are used for making soft yellow sugars as explained later on. This refinery raw is then washed, melted and put through the whole process all over again. The liquor, from which the crystals formed in repeated boilings have been removed as made, at length becomes so charged with impurities that further crystallization of sucrose is impossible and this residue, or final waste, is known as blackstrap molasses.
This manner of boiling white sugar has been called the “out and out” method, in contradistinction to the “in and in” method employed in boiling soft yellow sugars, of which a few words of explanation now follow.
In boiling soft yellow sugars, the aim is to produce a large number of small sucrose crystals having the property of attracting and combining with the molasses content of the liquor and that will retain some of the molasses after they are purged of mother liquor in the centrifugal machines. This process gives a sugar that may be described as a mechanical mixture of sucrose, invert sugar and the non-sugars in the molasses.
In the case of yellow sugars, the lighter the color the better price they bring. The greatest profit, therefore, is derived from the manufacture of sugars of the lightest color and carrying a reduced percentage of sucrose. In boiling such sugars, low-purity liquors from which the coloring matter has been removed as far as practicable by bone-char filtration are required. For the purpose, it is generally found most advantageous to use the liquors taken from white sugar massecuite at the point when, owing to repeated boilings, its purity has fallen so low that further extraction of pure white sucrose crystals is impossible.
As a result of the numerous filtrations through bone-char preparatory to reboiling in the manufacture of white sugar, these liquors are usually lighter in color than any of corresponding purity obtained in the refining process. Nevertheless, they are not necessarily the only liquors suitable for the purpose, and this particularly applies to the making of the lower grades of yellow sugars. It is, however, beyond the scope of this book to elaborate upon that phase of sugar refining. The object sought here is to give a general idea of how yellow sugars are boiled, without going into all the details.
As is the case with white sugars, yellow sugars are made by a succession of boilings in vacuum pans, the liquor used for each boiling or strike being that obtained from the massecuite of the previous strike. The operation is continued until the liquor becomes too low in purity and dark in color. Each successive strike boiled is lower in test than the preceding one, due to the fact that the sucrose crystals represent the purest part of the massecuite, and, consequently, each time they are removed the quality of the liquor is lowered. This accounts for the various grades of yellow sugar that are made, fifteen in all, starting with a creamy white and ending with a dark brown. The sucrose content of the best is about 92 per cent and that of the poorest about 80 per cent.
In making white sugars, the aim is to produce from liquors of high purity sucrose crystals that are pure white, hard and absolutely free from molasses.
In making yellow sugars, the object is to boil from low-purity liquors soft sucrose crystals that possess the property of attracting and retaining the molasses and to make this combination of crystals and molasses as complete as possible.
The essential difference between the two methods, as well as the appropriateness of the descriptive terms “out and out” and “in and in,” will be readily apparent.
The impurities in yellow sugars are natural and consist of invert sugar, glucose, organic non-sugars and salts, all of which were originally present in the raws or were formed in the process of refining.
It is not unusual to hear it said that yellow sugars are sweeter than granulated. To the average palate this is apparently so, but, as has been shown, granulated sugar contains 99.8 per cent of sucrose or sweetening matter, while the highest grade of yellow carries only 92 per cent. Soft sugars dissolve more readily on the tongue than granulated, and the syrup or molasses in them accentuates their sweet taste.
There are several other grades of sugar prepared for the consuming market, but lack of space precludes a description of them or the methods by which they are produced.
MECHANICAL DEPARTMENT
It is needless to say that the conveying, melting, filtering, boiling, drying, screening, weighing and packing of one thousand tons of sugar in twenty-four hours necessitates a great amount of steam and a multiplicity of machinery.
The boilers generate steam to drive huge pumps that deliver cold salt water to the condensers throughout the refinery, to drive vacuum pumps that make boiling and evaporation _in vacuo_ possible, and to drive large turbine or reciprocating engines that supply the electric power. The exhaust steam as it leaves the cylinders has a pressure of about fifteen pounds per square inch. It is conducted through pipes to the evaporators, pans, driers and tanks, where it is again used for concentrating the liquors, boiling in the pans, drying the sugar and keeping the liquors hot throughout the process. It leaves the various heating coils and tubes as hot water and is returned to the boilers for the generation of more steam.
Live steam, that is to say, steam just as it comes from the boilers, is used extensively in the vacuum pans for boiling the liquor to grain.
A refinery melting one thousand tons of raw sugar each day requires about 5500 boiler horse power. On the Atlantic coast coal is the fuel used, while on the Pacific coast oil is burned. The amount of fuel consumed in different refineries varies to some extent, but a fair average per ton of raw sugar melted is one and one-third barrels of oil, or one-third of a ton of coal.
In modern plants all the moving machinery, except the pumps and main engines, is usually driven by electric motors. This does away with many dangerous belts, as well as expensive transmission machinery. The motor drive is simple and efficient and therefore used extensively.
The mechanical department is under the general supervision of the superintendent, but in direct charge of a mechanical-electrical engineer. This man is known as the chief engineer, and he is directly responsible, not only for the operation of all the machinery in the plant together with its upkeep and repair, but he has also to cope with engineering problems that are constantly arising. Under his direction, a corps of draughtsmen is always busily engaged in planning and designing improvements and additions. He also maintains a force of mechanics, watching, operating and repairing the machinery. These men represent almost every trade, including machinists, blacksmiths, coppersmiths, tinsmiths, millwrights, boilermakers, riggers, masons, painters and many others.
The diversity of the mechanical work around a refinery is remarkable, and the engineer in charge must be a man of exceptional mechanical ability, as his duties include not only steam, electrical and civil engineering, but construction engineering of an advanced character. As refineries are always built on sites bordering on deep water, harbor engineering problems are also constantly before him.
In connection with every refinery there are many shops, where mechanical work incidental to repairs and construction is carried on. These shops are equipped with the necessary tools and implements for quick repairs and are under the supervision of the chief engineer. In addition, there is the cooper shop where many thousands of barrels are turned out daily, and the bag factory where twenty cotton bags and twenty burlap bags must be made for each and every ton of output packed in that manner.
The mechanical department of a modern refinery is as important as it is extensive, for failure in any one of its branches means costly delays. The machinery is run twenty-four hours each day, except Sundays, during about eleven months in the year. The plant is closed down the remaining thirty days for annual cleaning and repairs.
Intelligence and ability, tempered with good judgment, bring about the _esprit de corps_ that gives the necessary results. The mechanical is almost as important as the chemical department and, as before stated, it is subject to the general supervision of the chemical engineer.
LABORATORY
The chemical laboratory is really the heart of the institution, for upon it depends the success of every manufacturing operation. The superintendent of a refinery must possess a thorough knowledge of chemical engineering, for the process of sugar refining is largely chemical from beginning to end.
Competent chemical engineers, as distinguished from chemists, are rare, and yet their calling offers more promising prospects to young men than most other professions do today. It is clear to the intelligent observer that in these times of intensely keen competition, the manufacturer will, sooner or later, inevitably be driven to seek a considerable percentage of his profits in the utilization of by-products that now go to waste or bring but little return. The men to solve the manufacturing problems of the future will be chemical engineers. Broadly speaking, comparatively little has been done in this field in the United States, and its possibilities are incalculable.
In the laboratory, day and night, a corps of chemists is constantly engaged in the study of questions that arise in connection with the operation of the various departments. Polarizations for account of buyers and sellers of all raw sugars purchased, are made and checked there; hundreds of samples of liquors and syrups are tested daily for control work, as the purity of both must be known at all times and a record kept of their temperatures and densities. Samples of all the sugars entering the refining process, as well as of the finished product, are carefully analyzed, and upon these analyses are based elaborate calculations regarding yield and efficiency. The wash waters from the char filters are examined and tested frequently, the bone-char is tested every twenty-four hours as a check upon the process of revivification in the kilns, and once a month the bone-char is completely analyzed to determine the deterioration that has taken place in it.
Tests are made of materials used in the refining process, such as lime, soda, acids and lubricating oils; of the feed water for the steam boilers; of the fresh water used throughout the plant; and of the fuel, whether coal or oil. Even the gases from the fires under the boilers are tested as they pass through the smokestack, in order to determine whether or not the firemen perform their duties properly.
Taking all this in conjunction with frequent tests and experimental work on driers, condensers, evaporators and other apparatus, it will be seen that there is plenty to keep a large staff of chemists fully occupied.
In refinery work, what is to be feared more than anything is the house becoming “sour.” Raw sugars and sugar liquors, and particularly the sweet waters, have a tendency to ferment, and fermentation, like fire, if not checked and brought under control before it gains much headway, soon pervades the entire establishment, affecting all the liquors and syrups, thus turning the sucrose or sugar into glucose, which cannot be recrystallized. In a refinery of two million pounds daily capacity, there is double this quantity of sugar in the house in the form of liquors, syrups, sweet water, massecuite and raws. If all of this four million pounds turned “sour,” the money loss, with raw sugar worth four cents a pound, would be about one hundred and sixty thousand dollars. Such a contingency, while remote, clearly demonstrates that chemical control is an absolute necessity.
COST OF REFINING
In concluding that part of the story that deals with refining, some reference may be made to the refining cost and to the price at which refined sugar is sold.
The cost of refining sugar varies in different parts of the United States on account of the difference in the cost of commodities entering into the refining process, such as labor, fuel, cotton, burlap, containers, bone-char, etc. On the Pacific coast nearly all these items are higher than in New York, and consequently the cost of refining is probably greater.
In 1911 nearly all the sugar refiners of the United States appeared before the Hardwick Congressional committee at Washington and the testimony given by them before that body showed that the cost of refining ranged from 60 cents to 65 cents per 100 pounds.
On the day the Congressional committee began its investigation, raw sugar was selling in New York for 3.86 cents per pound, and the testimony regarding the cost of refining was no doubt based on this price for the raw sugar entering the refining operations.
It is therefore fair to assume that under normal conditions, with raw sugar at about 3¾ cents, the average cost of refining in the United States is 62½ cents per 100 pounds. This includes every item from the time the raw sugar is landed on the dock until the refined is loaded on the cars or boats for shipment. It includes the selling and overhead expenses, but not the transportation charges after the sugar leaves the refinery.
During the last six years (1909-14 inclusive) the actual differential in the United States between the purchase price of raw sugar and the selling price of refined has been 82½ cents per 100 pounds. The difference between this figure and the cost of refining represents the refiner’s gross profit; in other words, about 20 cents per 100 pounds, out of which he must pay for all additions and improvements to his plant. The remainder is available for returns on capital invested. This difference varies with the time of year and in different localities, but the average will probably hold good.
A refiner of cane sugar buys his raw product in the open market and must pay for all his operating and administration expenses and obtain his profit from the margin between the buying price of raw and the selling price of refined sugar. The cost of refining is not constant, as it varies with the fluctuating values of fuel, containers, labor, and particularly the cost of raw sugar. If it costs 62½ cents per 100 pounds to refine sugar with raws at 3.86 cents per pound, it will cost about 82½ cents per 100 pounds with raw sugars at 6 cents, assuming that such items as fuel, containers, labor, etc., remain constant. This is due to the greater value of the raw sugar lost in refining, to the heavier insurance premiums and higher interest charges. With high-priced raws, the margin between raws and refined must be proportionately greater to offset the increased cost of refining.
The refiner, like the consumer, would prefer to see sugar selling on a low basis, while the producer always hopes for the opposite.
SHIPPING DEPARTMENT
Here will be found every modern convenience for the rapid loading of cars and steamers. Adequate railway trackage is provided for the handling of shipments moving by rail, and on the waterfront side of the warehouses there is ample berth room for steamers that carry the sugar to cities and towns on the inland waterways and the seacoast, together with points tributary thereto. Facilities are also at hand for local delivery by drays.
Railroad cars are sometimes sent to refineries by water, on car barges, to be loaded with sugar and then towed to what are known as railroad terminals, where the cars are taken from the barges and started on their journey to destination. The capacity of a car varies from twenty-four thousand to one hundred thousand pounds. If an amount of sugar equal to that consumed in the United States in 1915 were loaded into cars containing 1000 sacks of 100 pounds each, it would require 81,087 cars, which would make up a train 768 miles long.
A large part of the product is delivered direct from the packing-room conveyors into the waiting cars and steamers, thus avoiding unnecessary handling. A single shipment frequently includes a number of different styles of package, and great care must be exercised to insure accuracy in count and description.
As dry granulated sugar readily absorbs moisture, every precaution must be taken to make the storage rooms thoroughly damp-proof, so that the sugar may always be in good condition when shipped from the refinery.
Shipments are made only on written orders from the sales department to the head of the shipping department. These orders set forth the name of the buyer, the kinds and quantity of sugar desired, the point to which the sugar is to go, the route by which it is to travel, the date on which it is to be shipped, and the terms of sale. At the proper time the sugar is loaded, shipped, and in due course delivered to the buyer.
MARKETING
The amount of sugar used in the United States in 1915 was 4,257,714 short tons. Of this, 3,389,175 tons were raw cane, the remainder consisting of 861,568 tons of domestic beet and 6,971 tons of foreign refined cane and beet. Of the 3,389,175 tons of raw cane, 150,000 tons were consumed in the raw state, and from the remainder, 3,239,175 tons, about 3,044,825 tons of refined sugar were produced. The per capita consumption was 83.83 pounds, and was made up of:
SHORT TONS PER CENT Refined made from raw cane 3,044,825 74.94 Domestic and foreign beet 862,694 21.23 Foreign refined cane 5,845 .14 Consumed in the raw state 150,000 3.69 --------- ------ 4,063,364 100.00
Among articles of food that contain a large percentage of sugar are jams, jellies, chocolate, canned fruits, condensed milk, confectionery, chewing gum and cordials. It is estimated by Willett & Gray that in 1915 the direct per capita consumption was 31.43 pounds, and that the remaining 52.40 pounds were used in various prepared or manufactured foodstuffs. Over ninety-nine per cent of all the cane sugar consumed in the United States is refined in New York, Boston, Philadelphia, New Orleans and San Francisco. The beet comes chiefly from California, Colorado, Michigan, Utah and Idaho; the maple from the New England states, Ohio and Canada; and the small amount of full duty-paying foreign cane from Java, Peru, Mexico, Central America and Santo Domingo.
During the past eleven years the consumption in the United States has grown at an average rate of 3.57 per cent per annum. In 1911, on account of the abnormally high prices, the increase was practically nil.
The annual per capita consumption of sugar in some of the other countries of the world is as follows:
1914 Servia 4.60 lbs. Greece 8.99 ” Bulgaria 9.94 ” Italy 10.45 ” Portugal 13.60 ” Spain 15.91 ” Roumania 17.12 ” Turkey 20.33 ” Russia 29.26 ” Finland 32.54 ” Austria-Hungary 37.38 ” France 39.01 ” Belgium 42.79 ” Holland 53.44 ” Norway 60.37 ” Sweden 60.48 ” Switzerland 74.87 ” Germany 74.95 ” England 89.69 ” Denmark 93.48 ”
The sale and distribution of large quantities of refined sugar is a serious problem and just as important as the production and the refining of the raw product. Competition is so keen, and the questions involved so complex, that the sale of the product really results in commercial warfare.
To dispose of the output of a large plant successfully requires great intelligence, a broad grasp of business principles, strict honor and integrity, and prompt, decisive action in times of fluctuating markets.
Sales managers of the sugar-refining companies of the United States command high salaries, for the success of the business depends to no small extent upon their ability and judgment. Their knowledge of human nature must be broad and sound and it is tested to the utmost in their selection of assistants and brokers, for representatives always reflect the ideals, principles and methods of the parent authority.
The selling of sugar by the refiner direct to the consumer has not been found practicable, as an organization complete enough to keep in touch with consumers in every city, town and village of the country would be so top-heavy and costly to maintain that the price of the commodity to the consumer would be needlessly increased.
As matters stand, people living in the frozen valleys of Alaska, in the scarcely accessible regions of the Rocky mountains and in the lumber and mining settlements of the West, many miles from railroads, can obtain their supply of sugar with almost the same facility as the residents of New York or San Francisco. A system of distribution that makes this possible leaves little to be desired, and a word or two concerning it will be timely at this point.
Sugar is sold by the refiner to the wholesale grocer through the medium of the refinery’s broker. From the wholesaler it goes to the retailer, who in turn delivers it to the consumer.
Brokers are important factors in distribution. In every large city and consuming center, each refinery is represented by its own brokers, who keep in constant touch with all the wholesale grocers and manufacturers of their district.
A thorough knowledge of men and methods, sound business principles, diplomatic talents of no mean order and the capacity to act rapidly, but coolly, in business crises are found combined in the successful broker. He occupies a position between the seller and buyer, and it is just as much his prime duty to see that in all transactions full justice is accorded to both as it is to sell the sugar.
Every refinery having its own broker in each consuming center, it follows that the competition for business among the brokers is very keen. When a broker obtains an order from a jobber or manufacturer, he telegraphs it to his principal. The order is usually confirmed and the goods shipped promptly. For his services the broker receives three cents for every one hundred pounds of sugar sold. This compensates him for the services of his salesmen and himself, his office expenses and cost of telegrams, which is heavy.
Manufacturers of foodstuffs of which sugar is an ingredient, buy their supplies through brokers. They do not resell the sugar as such, but use it only in the manufacture of their own special products.
Wholesale grocery jobbers, of whom there are about twenty-five hundred in the United States, are also very important factors in the distribution of sugar. As a rule, they are located in the large centers of population, and have efficient organizations for the purchase and resale of all kinds of foodstuffs. They deal in as many as three thousand different commodities, and their expense of doing business is apportioned over all of these items, thus reducing to a minimum the expense of handling any one of them. Generally speaking, they have large establishments where stocks of all kinds of goods are carried ready for immediate distribution. The aggregate capital tied up in these stocks throughout the country is enormous, but necessary, as the jobber must at all times be ready to deliver to the retailer whatever is wanted in any of his lines. Wholesale jobbers occupy a unique position in the scheme of things. They are to the commerce of the country what the bankers are to its finances. In other words, they are the bankers of commodities. Their operating staff consists, first, of the buyers, and, second, of the salesmen.
The buyers are men possessing special knowledge concerning the various articles handled by the house. For instance, in the grocery line one will buy nothing but teas and coffees, another canned goods, another sugar, and so on. These men as a rule have devoted years of study to the particular commodity which they are delegated to buy. They are shrewd, keenly alert and always ready to take advantage of market fluctuations in their favor. The margin of profit between the buying and selling price of any commodity is usually so small that the acumen of the buyer is an important factor in the final results.
The salesmen are trained, tactful, tireless and efficient. They travel from town to town and place to place, visiting every nook and corner where human beings congregate, in order to sell the goods carried by the firm. While his calling is a most useful one, the life of a “knight of the grip” is not always pleasant, as he meets with many deprivations and discomforts.
To compensate him for capital invested, for the expense of doing business and for the losses he incurs in bad debts and declining markets, the jobber probably obtains a gross return of fifteen cents on each one hundred pounds of sugar he sells.
The next important link in the chain is the retailer. It is roughly estimated that there are three hundred thousand retail grocers in the United States, many of whom handle and distribute almost as many articles as the jobber. Their lot on the whole is not cast in pleasant places, because of the severe competition they meet in selling their goods.
Competition is a word regarded almost with affection by the buyer, but for the seller of goods it is probably the most unpleasant one in the English language. There is an old axiom which reads: “Competition is the life of trade.” It may be so, but the expression was no doubt coined by a buyer.
Among sellers, competition is in direct proportion to the number engaged in any particular business. It therefore follows that as there are three hundred thousand retailers in the United States, and hundreds in each of all the large cities, the struggle to keep on their feet and continue their various enterprises must be severe. The number of failures occurring every year amply substantiates this assertion. Reckless and unscrupulous men engage in every business, and the competition thus forced on all others in their line is not only unfair, but positively dishonest. Any individual can break a price or introduce new and expensive experiments in selling terms, which must be followed with equally attractive terms by the other sellers, thus resulting in great loss to all. It is no satisfaction that such men finally fail and go out of business, for the losses sustained in the interim can never be recovered.
Another grave difficulty with which the retailer has to contend is the fact that the average individual to whom he delivers his wares is apt to be rather callous when pay-day comes around. It is sad, but true, that those best able to pay are sometimes the most unsatisfactory customers of the retail grocer.
A retailer’s expense of doing business is proportionately much greater than that of the wholesaler, and his losses, due to bad or uncollectible accounts, are much heavier. The cost of delivering goods to the consumer’s door is high, and a fact that should be remembered, but which is frequently overlooked, is that it costs the grocer just as much to deliver a five-pound package of sugar as a wagon-load. Householders are proverbially careless, and telephone calls for late and urgent deliveries are a source of great annoyance and expense.
To create a pleasing impression, the grocer must keep a clean, sanitary store, and the expense incident to attractive window and shelf displays to invite attention is an important item. Department and other stores in his town or neighborhood often advertise “leaders” to attract the buying public, in the hope of selling with these leaders other goods at a profit, or because they are overstocked with a particular commodity. Every retailer must, as a rule, meet this unfair competition or lose his trade.
Sugar more than any other staple article is used as a leader, and, as a result, the retail grocer’s profit on it is very small. What remains to him out of the selling price of one hundred pounds of sugar does not exceed thirty-five cents, and more than likely it has cost him twenty-five cents to sell it. It is the retail grocer’s employé who delivers sugar in the quantity desired to the housewife at her door, and through her hands the pure, glistening crystals reach the family table.
BEET SUGAR
SHORT REVIEW OF THE HISTORY OF BEET SUGAR
The extraction of sugar from beets dates back to 1747, when Andreas Marggraf, professor of physics in the Academy of Science of Berlin, discovered the existence of a sugar in beets similar in its properties to that obtained from cane.
The discovery was little utilized at first, however, and the manufacture of sugar from beets did not attain commercial importance for over half a century, when Franz Karl Achard, a pupil of Marggraf, made discoveries which led to the construction of the first beet-sugar factory in the world, in Silesia, in the year 1799.
The work of Achard soon attracted the attention of Napoleon Bonaparte, who appointed a commission of scientists to go to Silesia to investigate Achard’s factory. Upon their return, two small factories were constructed near Paris. Although these two factories were not altogether a success, the results attained greatly interested Napoleon, and in 1811 he issued a decree appropriating one million francs ($200,000) for the establishment of sugar schools, and compelling the farmers to plant a large acreage to sugar beets the following year. He also prohibited the further importation of sugar from the Indies after January 1, 1813.
As a result of these and other drastic decrees, three hundred and thirty-four factories were erected in France during the years 1812 and 1813, and their production was seven million seven hundred thousand pounds of sugar, or an average of eleven and one-half tons to the factory.
With the fall of Napoleon Bonaparte, disaster came upon this, one of his greatest achievements, and but one factory survived. The industry was destined to flourish again, however, under the reign of Louis Philippe. In 1836-37 there were five hundred and forty-two factories in France, producing thirty-five thousand tons of sugar, as compared with fourteen hundred and eight tons in Germany, which country had only recently begun the culture of beets.
When Napoleon III became emperor, he so stimulated the industry that in 1853 the French output had doubled. Meanwhile the Germans were making rapid strides, and in 1880 the German output of sugar exceeded that of France. As a result of legislative encouragement, Germany today is the largest beet-sugar producer in the world.
The first successful beet-sugar factory in the United States was constructed by E. H. Dyer, at Alvarado, California, in 1879. The next successful factory was erected at Watsonville, California, in 1888, by Claus Spreckels. The Oxnard brothers followed with the construction in 1890 of a factory at Grand Island, Nebraska, one at Norfolk, Nebraska, and a third at Chino, California, the last built in 1891.
From this it will be seen that the commercial production of beet sugar in the United States really dates back to about 1890, since only three factories of small capacity had been established prior to that date. The development of the industry since the year 1892 has been rapid, and the general results of the beet industry in the United States in 1915 showed the following:
Factories in operation 67 Acres of beets harvested 611,301 Average yield of beets per acre 10.10 short tons Beets worked 6,150,293 ” Sugar manufactured 874,220 ”
The season of 1916 promises a notable increase in tonnage.
THE SUGAR BEET
The botanical name of the sugar beet is _Beta vulgaris_. It grows exclusively in the temperate zone, and with satisfactory soil and climatic conditions a yield of thirty tons per acre has resulted. The average yield in the United States, however, is slightly over ten tons per acre. There are many varieties of beets, some of which do better in one locality than another, so that great care must be used in the selection of the seed.
The beet, unlike sugar cane, grows below the ground, is white in color and shaped like the ordinary carrot, but larger. The beets vary greatly in size, depending upon variety, soil and climatic conditions, the average weight ranging between one and two pounds.
The foliage has a rich, brilliant green color and grows to a height of about fourteen inches. The leaves are numerous and broad and grow in a tuft from the center or crown of the beet, which is usually level with or just above the ground surface.
The average composition of a sugar beet is about as follows:
Sugar 17.3 per cent Marc or pulp 4.4 ” Ash and organic non-sugar .7 ” Water 77.6 ”
The value of the beet to a factory depends on the amount and purity of the sugar content. Factories as a rule decline to purchase beets containing less than twelve per cent of sucrose, as it is unprofitable to handle them. In order to induce the farmer to devote particular care and attention to the culture of his fields and thus increase the sugar content, the factories pay a premium for beets containing over fifteen per cent of sugar. The premium is usually twenty-five cents per ton of beets for each additional one per cent of sugar. Encouraged by this bonus, the California grower has improved the quality of his beets, until today they contain on an average about eighteen per cent of sugar of a purity from eighty to eighty-four.
SELECTION OF THE SOIL
The sugar beet, like sugar cane, needs a peculiar soil and climate for its successful cultivation. The most important requirement is that the soil shall contain a large supply of plant food, be rich in humus and have the property of retaining a great deal of moisture. A certain amount of alkali is not necessarily detrimental, as sugar beets are not especially susceptible to injury from this salt. The ground should be fairly level and well drained, especially where irrigation is practiced.
While the physical character is of secondary importance, as generous crops are grown in sandy soil as well as in heavy loams, still the ideal soil is a sandy loam, _i. e._, a mixture of organic matter, clay and sand. A subsoil of gravel, or the presence of hard-pan, is not desirable, as cultivation to a depth of from twelve to fifteen inches is necessary to produce the best results.
Climatic conditions, temperature, sunshine, rainfall and winds have an important bearing upon the success of beet culture. A temperature ranging from 60 degrees to 70 degrees Fahrenheit during the growing months is most favorable. Sixteen inches of rainfall are necessary to raise an average crop of beets without irrigation. High winds are very harmful, as they generally crust the land and prevent the young beets from coming through the ground. The best results are obtained along the coast of southern California, where warm, sunny days succeeded by cool, foggy nights seem to meet every requirement. Sunshine of long duration but not of great intensity is the most important factor in the successful cultivation of sugar beets. The nearer the equator is approached, the poorer the beets become in sucrose because of the shorter days and the greater heat of the sun. Beets have never been raised with success in the hot interior valleys, as the hot days followed by warm, dry nights sap the vitality of the plant. In the elevated Rocky mountain region of Colorado and Utah, where the temperature is high during the daytime but where the nights are cool, the quality of the beet is excellent.
In Michigan the long summer days and the influence of the great lakes result in satisfactory climatic conditions for sugar-beet culture, and the crops raised in that state are large.
In order to cultivate beets successfully the land must be properly prepared. Deep ploughing is the first principle of beet culture. It allows the roots to penetrate the subsoil without much obstruction, thereby preventing the beet from growing out of the ground, besides enabling it to extract considerable nourishment and moisture from the lower soil. If the latter is too hard, the roots will not penetrate it readily and, as a result, the plant will be pushed up and out of the earth during the process of growth. A hard subsoil is impervious to water and prevents proper drainage. It should not be too loose, however, as this allows the water to pass through more freely than is desirable.
The character of the surface soil is equally important. Careful preparation by harrowing should be done to afford a finely pulverized and clean bed for the seed.
To sum up, the soil should be deep, fairly fine and easily penetrable by the roots. It should also be capable of retaining moisture and at the same time admit of a free circulation of air and good drainage.
PLANTING
The preliminary preparation of the ground finished, the seed should be put in as soon as the soil is firm enough to allow it to germinate readily and the young plants to grow normally. The time of planting varies according to climatic conditions. In California planting begins as a rule in December and ends in March, while in Utah, Colorado and Michigan it ranges from March until May.
About twenty pounds of seed to the acre are required to produce a satisfactory stand. The seed is planted in rows, about eighteen inches apart, and is drilled in solidly to a depth of from three-quarters to one and a half inches. The latter is the maximum, as any greater depth than this weakens the plant and should, therefore, be avoided. The soil around the seed is well packed by the planter in order to draw the moisture necessary for germination.
The production of beet seed presents many problems; the chief one is to obtain the particular kind of seed that will bring forth a hardy beet containing a large percentage of sugar of a high purity. The beets from which the seed is produced are selected with the greatest care, and for nearly a century the Luther Burbanks of Europe have devoted their time and skill to improving the quality. Until recently, practically all of the beet seed used in the United States was imported from Europe. Since the outbreak of the great war in 1914, however, the difficulties attendant upon securing a supply have caused the beet growers to turn their attention to raising seed in this country. Their efforts have been rewarded with a fair measure of success, and while the cost is greater than that of European seed, the germinating properties have proven to be excellent. The best results have been obtained in Idaho. Owing to the fact that the culture of the beets and the picking and sorting of the seed are done chiefly by hand, labor enters largely into the cost of production, and consequently, under normal conditions, the growers in the densely populated countries of Europe have a great advantage over those in the United States, where the main difficulty is securing labor for the field work.
Like sugar cane, beets are subject to plant diseases of various kinds, as well as to injury by insect pests, and great care has to be exercised to ward off these dangers.
Probably no other crop exhausts the soil so rapidly as beets, and, if they are planted for many years in succession, they deteriorate year by year. On the other hand, if crops are rotated so that beets are grown in the same ground every third year, peas, beans or grain being raised the other two years, it is a remarkable fact that all of these crops will improve each year. This is due to the intensive cultivation of the beets and to the humus left in the ground in the form of rootlets. Experience has taught the farmer that no other crop is so beneficial to the soil as beets grown in the right rotation and with proper care.
THINNING
As soon as the beets are up and the rows clearly defined, thinning becomes necessary. This is one of the most important features of beet culture and is a tedious and expensive operation. It consists of cutting out the plants so that individual roots remain, spaced about eight inches apart. The work is done by hand, a hoe being used to block out the spaces, and the roots surrounding the one which it is desired to retain are pulled up. Due partly to faulty germination, but principally to defective thinning of the beets, in which operation a great many of the small, tender beet plants are injured or killed, very much less than the theoretical number of mature beets are secured per acre. With rows eighteen inches apart and a plant every eight inches in the row, 43,000 beets per acre should be obtained, which, at an average weight of one and one-half pounds per beet, would mean 32.25 tons. Owing, however, to the facts just mentioned and to other causes, the actual yield is always much less. The average in California for a number of years past has been only 10.68 tons per acre.
CULTIVATION
The purpose of cultivation is two-fold; first, to retain the moisture in the soil, and, second, to destroy the weeds and grass, as in the early stages of the growth of the beets weeds might spoil the stand by choking the plants.
Cultivation should be continued until the plants have attained such a size that the leaves cover the ground. It increases the fertility of the soil by opening the land to the atmosphere, thus facilitating the penetration of oxygen and absorption of air moisture and the resulting decomposition and assimilation of nutritious elements.
HARVESTING AND TOPPING
The time when harvesting takes place depends on the many factors that influence the growth and maturing of the beet. In the colder countries the harvesting lasts from September until the ground becomes frozen, while in warmer climates like that of California, where the seed is planted early, harvesting begins about July first and lasts for a period of from seventy-five to ninety days.
The beets are first loosened by means of a specially shaped plough, called the “puller,” which lifts them from the ground. They are then picked up by hand and the crown of each beet, together with the leaves, is cut off with a large knife. The leaves contain no sugar, and are, therefore, not taken into the factory, but are utilized for stock feeding, being quite valuable for this purpose. The sugar contained in the crown is accompanied by so many organic salts that it does not pay to extract it.
The topped beets are then loaded into wagons or railroad cars and transported to the factory, at which point they are carefully weighed. In this country most of the beets are raised by farmers and sold under contract to the factories, at so much per ton, so that the determination of the exact weight and sucrose content is important. For the season of 1915 the average price paid to the farmers for beets was $5.67 per ton.
On arrival at the factory a certain number of beets are taken from every wagon- or car-load, and these represent a fair average of all the beets of that particular delivery. They are sent to the laboratory and their exact weight ascertained, after which they are trimmed of all adhering roots, leaves and parts of the crown, if not properly topped in the field. Any remaining soil is carefully brushed off and the beets thoroughly cleaned. They are then reweighed and the difference between this and the first weight is the tare. This difference represents a certain percentage of the total of the sample beets weighed, and that small percentage is deducted from the gross weight of the total load. In this way the exact net weight of beets delivered by the farmer is determined and he is paid according to this net weight.
The sugar content of the beet and the purity of the juice must now be ascertained, for the price paid the farmer varies according to the amount of sugar the beet contains. As in the case of weighing, sampling and polarizing raw cane sugar, representatives of both parties—the farmer and the factory—are present when all weights are taken and tests made. There are several different methods for determining the percentage of sugar in the beet and the purity of the juice, but the following gives a fair idea of the general practice.
The sample beets having been cleaned, are cut into quarters, one-quarter of each beet being taken for the general sample. This general sample is placed in a grinding or shredding machine, the beets are disintegrated to a fine pulp and thoroughly mixed. A specific amount of this fine pulp is then accurately weighed and placed in a copper pan or dish called a capsule. A small quantity of dilute lead solution is introduced to assist in clarifying, and sufficient water added to bring the volume up to 200 cubic centimeters. It is then heated for about twenty minutes and vigorously agitated, so that the sugar-bearing juice of the beet will mix evenly with the water that was added. The mixture, after being allowed to stand for several minutes, is filtered through paper and a certain amount placed in the observation tube of a polariscope. The instrument will show the amount of sugar in the solution, and by multiplying the reading by two the per cent of sugar in the beets will be found. If in preparing the sample only sufficient water had been added to bring it to a volume of 100 cubic centimeters, the polariscope would give a direct reading of the percentage of sugar in the beets. Practice has demonstrated, however, that the method described is the more accurate.
To ascertain the purity of the juice, the procedure is as follows: A part of the shredded sample is taken and the juice is squeezed out of it. The amount of sugar in this juice is determined by aid of the polariscope, and a Brix spindle shows the amount of solids it contains. By dividing the polarization by the Brix and multiplying by 100 the purity is obtained, which means the percentage of pure sugar in the total amount of solids contained in the solution.
The purity of the juice has an important bearing on the subsequent manufacture of the sugar. It is difficult and costly to extract sugar from low-purity juices, and the loss of sugar in the process is very high. The reverse is naturally true if the juices have a high purity. The purity of the juice in the beet is materially affected during the growing period by climatic conditions, rainfall, irrigation, fertilization, state of soil and cultivation. Great care and attention must be given the beet to insure high purity and heavy content of sugar.
From the above it will be seen how the net weight and the percentage of sugar in any particular wagon- or car-load of beets are ascertained, as well as the purity of all the beets that enter a factory. The efficiency of the work in a factory is based on the figures thus obtained.
MANUFACTURE OF BEET SUGAR
The process of making sugar from the beet is highly technical in its details and cannot be fully discussed within the scope of this work. A brief description, however, will give an idea of the general methods followed.
The process of manufacture may be classified under seven headings:
1. Transportation and cleaning of beets. 2. Extraction of juice, slicing and diffusion. 3. Purification, carbonation, filtration, concentration and sulfitation. 4. Formation of grain. 5. Partial drying, purging crystals from syrup in centrifugals. 6. Final drying. 7. Packing.
TRANSPORTATION AND CLEANING
The beets, after delivery to the factory, are stored in V-shaped bins, in the bottom of which is a flume covered by removable boards. By removing the boards, one at a time, the beets are fed into the flume, where a swift current of water floats them into the factory. From this flume the beets are lifted by means of a large wheel, a helical screw or any other suitable device, and discharged into a washer.
The common form of washer consists of a horizontal, semi-cylindrical tank provided with rotating, kicking or stirring arms for keeping the beets in motion. In this tank the beet is completely cleaned and separated from adhering earth, weeds and pebbles.
The beets are delivered from the washer into an elevator, which takes them to a point near the top of the factory and discharges them into automatic weighing and recording scales. From the scales the beets fall by gravity into the slicing machines.
EXTRACTION OF JUICE, SLICING AND DIFFUSION
The slices are made in various shapes and forms. The slicing machines consist of revolving, corrugated knives which cut the beets into long, thin slices or “cossettes.” The object is to produce slices which expose the greatest amount of surface, and yet sufficiently firm to lie not too closely together when placed in the diffusion battery, thereby preventing the circulation of the diffusion liquors. The cossettes are conveyed on an endless belt, or through a hopper, to the cells of the diffusion battery.
As the term implies, the juice in the beet is extracted by diffusion, and not by crushing, as in the case of cane. When two liquids, separated by a membrane, are brought in direct contact with each other and allowed to stand for a time, they mix uniformly without the assistance of mechanical or other force.
Beets are made up of a great number of plant cells, the walls of which are porous membranes. These cells are placed in contact with water or juice of lesser sugar content than the juice in the plant cell, in consequence of which the juice is gradually diffused from the beet and carried away in the circulating water which is added. When this water, or rather juice, has reached a certain stage of concentration, it is drawn out of the cells and sent to the next stage in the process of manufacture.
A diffusion battery, or the apparatus in which the process of diffusion is carried on, consists of a number of tanks or cells, usually from ten to fourteen, cylindrical in shape and terminating in truncated cones provided with covers. There are two ways of arranging the cells of a diffusion battery; in the one case the cells are placed in a straight line; in the other they are grouped in a circle. These cells are filled with cossettes in rotation, and water is introduced into the one in which the cossettes were first placed.
Thus the water enters the tank in which the cossettes are nearly exhausted of their sugar, and it flows successively through the other cells that contain cossettes of greater sugar content until the last cell, or the one containing fresh cossettes, is reached. The juice passing through this cell is alternately sent to the measuring tank or to the next cell, which has just been filled with fresh cossettes. The process is continuous, one cell being emptied of exhausted cossettes while another is being filled with fresh ones, and the juice flowing either to the measuring tank or to the freshly filled cell.
The exhausted cossettes, now called pulp, are dropped from the bottom of the diffusion tanks into a large bin, from which they are conveyed or pumped to pulp separators and presses for the separation of the surplus water. This pressed pulp is usually stored in large bins or silos, where it is allowed to ferment before being fed to cattle.
Recently the practice of drying the pulp has been carried on to a large extent. In this process the moisture in the pulp is reduced to ten per cent, the same proportion as in cured hay. Dried to this point, it is packed in bags and may be stored for an indefinite period without deteriorating. After being treated thus it forms an excellent stock food, particularly if waste molasses is sprayed on it before drying.
PURIFICATION OF JUICE, CARBONATION AND FILTRATION
The diffusion juice obtained as above described is quite dark in color, and after passing through the measuring tanks it is conveyed to carbonation tanks where it is treated with from three to four per cent of caustic lime in the form of a thick milk.
After being thoroughly agitated, the mixture is treated with carbonic acid gas obtained from the lime-kilns, as the result of the decomposition of limestone and the combustion of the fuel used for burning it.
By this process some of the impurities in the juice are removed and the color reduced to a brilliant amber. As is the case in the cane mills and refineries, it is essential to keep the juice hot throughout the process. The carbonation is continued until the juice is only slightly alkaline, when it is passed through filter presses for the removal of the precipitated lime carbonate and other solid matter. The solid matter in suspension is retained in the frame of the press, and, as soon as the frame is full, the cake is washed by passing water through it. When the sugar content of the cake has been sufficiently reduced, the press is opened and the cake discharged and sent to the fields to be used as a fertilizer.
As a rule, the filtration is repeated for the elimination of any solids that may have passed through the first filtration. This double filtration is usually practiced in all the filtrations in the course of the juice through the factory.
The juice after being filtered a second time is again treated with carbonic acid gas for the further reduction of the caustic lime and then undergoes a third filtration, following which it is sent to the evaporators for concentration.
CONCENTRATION OF JUICE
When the juice reaches the evaporators it contains about eighty-two per cent of water, which, by concentration, must be reduced to about forty per cent. As already explained, the removal of water is generally accomplished in multiple-effects. The apparatus consists of a number of boiling bodies connected in such a manner as to secure a progressive decrease in atmospheric pressure.
The thin juice enters the first body where evaporation takes place under a slight pressure. The steam for this evaporation is usually the waste or exhaust from the engines and pumps. The vapors generated by the evaporation of water from the juice in the first body enter the heating tubes of the second body and are used in further concentrating the somewhat concentrated juice from the first body. The evaporation in this second body is conducted at a higher vacuum and corresponding lower temperature than in the first body. This proceeding is continued until five or even six bodies are used in the series. The last body is usually under a vacuum of about twenty-six inches of mercury.
It is obvious that by this arrangement the concentration of the thin juice is effected with the maximum of economy, direct steam being admitted into the first body only and the rest of the operation accomplished by the steam generated in the boiling of the juice.
SULFITATION
The thickened liquor leaving the last body of the evaporators is sent to the sulphur station and treated with sulphur fumes, in order to further precipitate the soluble impurities and reduce the color of the liquor. It is then heated to boiling point in closed tanks and passed through a double set of cloth filters. This is the final process in the purification of the beet juice, and it is then ready for graining.
In a cane-sugar refinery no sulfitation of the liquor takes place, and in a beet factory there is no char filtration for removal of color and impurities in the liquor. These two points constitute the main difference in the methods of making white sugar from the cane and the beet in the United States. In Europe, however, many factories make a raw beet sugar, which is subsequently refined with the aid of bone-char.
FORMATION OF GRAIN
The formation of the crystallized grain and its progress through the vacuum pans, centrifugals, driers, granulators and screens, and into the bags in the packing room, is identical with the process in a cane refinery, which has already been described.
STEFFEN PROCESS
In some of the beet factories the sugar left in the final molasses is extracted by what is known as the Steffen process. The final low-purity molasses is diluted with water and cooled to a very low temperature, after which finely powdered lime is constantly added to the solution at a uniform and slow rate. The sugar combines with the lime and a saccharate of lime is formed which is insoluble in the liquid. The suspended matter or saccharate is then separated and washed in filter presses.
The cake from these filter presses, which is the saccharate of lime, is mixed with sweet water to a consistency of cream and takes the place of milk of lime in the carbonation process. When the Steffen process is employed, about ninety per cent of the sugar originally in the beet is extracted. The loss of sugar that does take place is accounted for in the exhausted cossettes or pulp, in the pulp water which surrounds them when they are dumped from the diffusion cells, in the cake and wash waters from the carbonation presses and in the waste and wash waters from the Steffen process. As the water used in washing the saccharate press cake is rich in fertilizing qualities, it is used for irrigating the lands adjoining the factory.
The 6,511,274 tons of beets harvested in the United States during the season of 1915 contained an average of 16.49 per cent of sucrose, of which 14.21 per cent found its way into the sacks as white sugar. The difference, 2.28 per cent, represented the loss in working up the beets. As only a few factories, however, were using the Steffen process, a considerable amount of sugar was left in the waste molasses. For the same period, the beets produced in California contained 17.82 per cent of sugar, of which 15.64 per cent found its way into the sacks, showing a loss of only 2.18 per cent. This may be accounted for by the fact that probably more of the California factories were equipped with the Steffen process than the average for the United States, and that the purity of the juices of California beets was higher than the average for the United States.
A factory equipped with the Steffen process and running on beets containing 17.82 per cent sugar, with a purity of 82, should lose not over 1.9 per cent of the sugar in the beet. The same factory without the Steffen process would probably lose 5.04 per cent of the sugar.
It is interesting to know that, according to the testimony given before the Hardwick committee, the average cost of producing and selling one hundred pounds of white beet sugar in the United States today is about three dollars and fifty cents. The selling price, which is from ten to twenty cents per one hundred pounds less than the selling price of refined cane sugar, fluctuates with the value of raw cane sugar. For instance, if raw cane sugar is selling in New York at four dollars per one hundred pounds, the selling price of refined cane will probably be four dollars and eighty cents. Beet sugar, therefore, would be four dollars and seventy cents or four dollars and sixty cents. On the other hand, if raw cane were selling for three dollars per one hundred pounds, refined would probably be three dollars and eighty cents and beet sugar three dollars and seventy or three dollars and sixty cents. In the one case the beet factory makes a large profit; in the other a very small profit.
As the value of raw sugar is determined absolutely by the law of supply and demand in the world’s markets, it is clear that the fortune or misfortune of the beet-sugar producer is beyond his control.