Chapter 2

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AMERICAN MILLING METHODS.

[Footnote 1: A paper read before the meeting of the Pennsylvania State Millers Association at Pittsburgh, Pa., by Albert Hoppin, Editor of the _Northwestern Miller_.]

By ALBERT HOPPIN.

To speak of the wonderful strides which the art of milling has taken during the past decade has become exceedingly trite. This progress, patent to the most casual observer, is a marked example of the power inherent in man to overcome natural obstacles. Had the climatic conditions of the Northwest allowed the raising of as good winter wheat as that raised in winter wheat sections generally, I doubt if we should hear so much to-day of new processes and gradual reduction systems. So long as the great bulk of our supply of breadstuffs came from the winter wheat fields, progress was very slow; the mills of 1860, and I may even say of 1870, being but little in advance, so far as processes were concerned, of those built half a century earlier. The reason for this lack of progress may be found in the ease with which winter wheat could be made into good, white, merchantable flour. That this flour was inferior to the flour turned out by winter wheat mills now is proven by the old recipe for telling good flour from that which was bad, viz.: To throw a handful against the side of the barrel, if it stuck there it was good, the color being of a yellowish cast. What good winter wheat patent to-day will do this? Still the old time winter wheat flour was the best there was, and it had no competitor. The settling up of the Northwest which could not produce winter wheat at all, but which did produce a most superior article of hard spring wheat, was a new factor in the milling problem. The first mills built in the spring wheat States tried to make flour on the old system and made a most lamentable failure of it. I can remember when the farmer in Wisconsin, who liked a good loaf of bread, thought it necessary to raise a little patch of winter wheat for his own use. He oftener failed than succeeded, and most frequently gave it up as a bad job. Spring wheat was hard, with a very tender, brittle bran. If ground fine enough to make a good yield a good share of the bran went into the flour, making it dark and specky. If not so finely ground the flour was whiter, but the large percentage of middlings made the yield per bushel ruinously small. These middlings contained the choicest part of the flour producing part of the berry, but owing to the dirt, germ, and other impurities mixed with them, it was impossible to regrind them except for a low grade flour. Merchant milling of spring wheat was impossible wherever the flour came in competition with winter wheat flours. At Minneapolis, where the millers had an almost unlimited water power, and wheat at the lowest price, merchant milling was almost given up as impracticable. It was certainly unprofitable. To the apparently insurmountable obstacles in the way of milling spring wheat successfully, we may ascribe the progress of modern milling. Had it been as easy to raise good winter wheat in Wisconsin and Minnesota as in Pennsylvania and Ohio, or as easy to make white flour from spring as from winter wheat, we should not have heard of purifiers and roller mills for years to come.

The first step in advance was the introduction of a machine to purify middlings. It was found that the flour made from these purified middlings was whiter than the flour from the first grinding and brought a better price than even winter wheat flours. Then the aim was to make as many middlings as possible. To do this and still clean the bran so as to make a reasonable yield the dress of the burrs was more carefully attended to, the old fashioned cracks were left out, the faces and furrows made smooth, true, and uniform, self-adjusting drivers introduced, and the driving gear better fitted. Spring wheat patents rapidly rose to the first place in the market, and winter wheat millers waked up to find their vantage ground occupied by their hitherto contemned rivals. To their credit it may be said that they have not been slow in taking up the gauntlet, and through the competition of the millers of the two climatically divided sections of this country with each other and among themselves the onward march of milling progress has been constantly accelerated. Where it will end no man can tell, and the chief anxiety of every progressive miller, whether he lives in Pennsylvania or Minnesota, is not to be left behind in the race.

The millers of the more Eastern winter wheat States have a two-fold question to solve. First, how to make a flour as good as can be found in the market, and second, how to meet Western competition, which, through cheap raw material and discriminating freight rates, is making serious inroads upon the local markets. Whether the latter trouble can be remedied by legislature, either State or national, or not, remains to be proven by actual trial. That you can solve the first part of the problem satisfactorily to yourselves depends upon your readiness to adopt new ideas and the means you have at hand to carry them out. It is manifestly impossible to make as good a flour out of soft starchy wheat as out of that which is harder and more glutinous. It is equally impossible for the small mill poorly provided with machinery to cope successfully with the large merchant mill fully equipped with every appliance that American ingenuity can suggest and money can buy. I believe, however, that a mill of moderate size can make flour equally as good as the large mill, though, perhaps, not as economically in regard to yield and cost of manufacture.

The different methods of milling at present in use may be generally divided into three distinct processes, which, for want of any better names, I will distinguish as old style, new process, and gradual reduction. Perhaps the German division of low milling, half high milling, and high milling is better. Old style milling was that in general use in this country up to 1870, and which is still followed in the great majority of small custom or grist mills. It is very simple, consisting of grinding the wheat as fine as possible at the first grinding, and separating the meal into flour, superfine or extra, middlings, shorts, and bran. Given a pair of millstones and reel long enough, and the wheat could be made into flour by passing through the two. Because spring wheat was so poorly adapted to this crude process, it had to be improved and elaborated, resulting in the new process.

At first this merely consisted of purifying and regrinding the middlings made in the old way. In its perfected state it may be said to be halfway between the old style and gradual reduction, and is in use now in many mills. In it mill stones are used to make the reductions which are only two in number, in the first of which the aim of the miller is to make as many middlings as he can while cleaning the bran reasonably well, and in the second to make the purified middlings into flour. In the most advanced mills which use the new process, the bran is reground and the tailings from the coarse middlings, containing germ and large middlings with pieces of bran attached, are crushed between two rolls. These can hardly be counted as reductions, as they are simply the finishing touches, put on to aid in working the stuff up clean and to permit of a little higher grinding at first. Regarding both old style and new process milling, you are already posted. Gradual reduction is newer, much more extensive, and merits a much more thorough explanation. Before entering upon this I will call your attention to one or two points which every miller should understand.

The two essential qualities of a good marketable flour are color and strength. It should be sharply granular and not feel flat and soft to the touch. A wheat which has an abundance of starch, but is poor in gluten, cannot make a strong flour. This is the trouble with all soft wheats, both winter and spring. A wheat which is rich in gluten is hard, and in the case of our hard Minnesota wheat has a very tender bran. It is comparatively easy to make a strong flour, but it requires very careful milling to make a flour of good color from it. Probably the wheat which combines the most desirable qualities for flour-making purposes is the red Mediterranean, which has plenty of gluten and a tough bran, though claimed by some to have a little too much coloring matter, while the body of the berry is white. By poor milling a good wheat can be made into flour deficient both in strength and color, and by careful milling a wheat naturally deficient in strength may be made into flour having all the strength there was in the wheat originally and of good color. Good milling is indispensable, no matter what the quality of the wheat may be.

The idea of gradual reduction milling was borrowed by our millers from the Hungarian mills. There is, however, this difference between the Hungarian system and gradual reduction, as applied in this country, that in the former, when fully carried out, the products of the different breaks are kept separate to the end, and a large number of different grades of flour made, while in the system, as applied in this country, the separations are combined at different stages and usually only three different grades of flour made, viz.: patent, baker's, or as it is termed in Minnesota, clear flour, and low grade or red dog. In the largest mills the patent is often subdivided into first and second, and they may make different grades of baker's flour, these mills approaching much nearer to the Hungarian system, though modifying it to American methods and machinery. In mills of from three to five hundred barrels daily capacity, it is hardly possible or profitable to go to this subdivision of grades, owing to the excessive amount of machinery necessary to handling the stuff in its different stages of completion. The Hungarian system has, therefore, been greatly modified by American millers and milling engineers to adapt it to the requirements of mills of average capacity. This modified Hungarian system we call gradual reduction. It can be profitably employed in any mill large enough to run at all on merchant work. So far it has not been found practicable to use it in mills of less than one hundred and twenty-five to one hundred and fifty barrels capacity in twenty-four hours, and it is better to have the mill of at least double this capacity.

Gradual reduction, as its name implies, consists in reducing the wheat to flour, shorts, and bran, by several successive operations or reductions technically called breaks, the process going on gradually, each break leaving the material a little finer than the preceding one. Usually five reductions or breaks are made, though six or seven may be used. The larger the number of breaks the more complicated the system becomes, and it is preferable to keep it as simple as possible, for even at its simplest it requires a good, wide-awake thinking miller to handle it successfully. When it is thoroughly and systematically carried out in the mill it is without question as much in advance of the new process as that is ahead of the old style of milling.

In order that I may convey to you as clear an idea of gradual milling reduction as possible, I will give as fully as possible the programme of a mill of one hundred and fifty barrels maximum daily capacity designed to work on mixed hard and soft spring wheat, and which probably will come much nearer to meeting the conditions under which you have to mill than any other I have found readily obtainable. I have chosen a mill of this size, first, because following out the programme of a larger one would require too much time and too great a repetition of details and not give you any clearer idea of the main principles involved, and secondly, because I thought it would come nearer meeting the average requirements of the members of your association. Your worthy secretary cautioned me that I must remember that I was going to talk to winter wheat millers. The main principles and methods of gradual reduction are the same, whether applied to spring or winter wheat; the details may have to be varied to suit the varying conditions under which different mills are operated. For this programme I am indebted to Mr. James Pye, of Minneapolis, who is rapidly gaining an enviable and well deserved reputation as a milling engineer, and one who has given much study to the practical planning and working of gradual reduction mills.

And right here let me say that no miller should undertake to build a gradual reduction mill, or to change over his mill to the gradual reduction system, until he has consulted with some good milling engineer (the term millwright means very little nowadays), and obtained from him a programme which shall fit the size of the mill, the stock upon which it has to work, and the grade of flour which it is to make. This programme is to the miller what a chart is to the sailor. It shows him the course he must pursue, how the stuff must be handled, and where it must go. Without it he will be "going it blind," or at best only feeling his way in the dark. A gradual reduction mill, to be successful, must have a well-defined system, and to have this system, the miller must have a definite plan to work by. But to go on with my programme.

The wheat is first cleaned as thoroughly as possible to remove all extraneous impurities. In the cleaning operations care should be taken to scratch or abrade the bran as little as possible, for this reason: The outer coating of the bran is hard and more or less friable. Wherever it is scratched a portion is liable to become finely comminuted in the subsequent reductions, so finely that it is impossible to separate it from the flour by bolting, and consequently the grade of the latter is lowered. The ultimate purpose of the miller being to separate the flour portion of the berry from dirt, germ, and bran it is important that he does not at any stage of the process get any dirt or fine bran speck or dust mixed in with his flour, for if he does he cannot get rid of it again. So it must be borne in mind that at all stages of flouring, any abrasion or comminution of the bran is to be avoided as far as possible.

After the wheat is cleaned, it is by the first break or reduction split or cut open, in order to liberate the germ and crease impurities. As whatever of dirt is liberated by this break becomes mixed in with the flour, it is desirable to keep the amount of the latter as small as possible. Indeed, in all the reductions the object is to make as little flour and as many middlings as possible, for the reason that the latter can be purified, while the former cannot, at least by any means at present in use. After the first break the cracked wheat goes to a scalping reel covered with No. 22 wire cloth. The flour, middlings, etc., go through the cloth, and the cracked wheat goes over the tail of the reel to the second machine, which breaks it still finer. After this break the flour and middlings are scalped out on a reel covered with No. 22 wire cloth. The tailings go to the third machine, and are still further reduced, then through a reel covered with No. 24 wire cloth. The tailings go to the fourth machine, which makes them still finer, then through a fourth scalping reel the same as the third. The tailings from this reel are mostly bran with some middlings adhering, and go to the fifth machine, which cleans the bran. From this break the material passes to a reel covered with bolting cloth varying in fineness from No. 10 at the head to No. 00 at the tail. What goes over the tail of this reel is sent to the bran bin, and that which goes through next to the tail of the reel, goes to the shorts bin. The middlings from this reel go to a middlings purifier, which I will call No. 1, or bran middlings purifier. The flour which comes from this reel is sent to the chop reel covered at the head with say No. 9, with about No. 5 in the middle and No 0 at the tail. You will remember that after each reduction the flour and middlings were taken out by the scalping reels. This chop, as it is now called, also goes to the same reel I have just mentioned. The coarse middlings which go over the tail of this reel go to a middlings purifier, which I will designate as No. 2. These go through the No. 0 cloth at the tail of the reel purifier No. 3; those which go through No. 5 cloth got to purifier No. 4; while all that goes through the No. 9 cloth at the head of the reel is dropped to a second reel clothed with Nos. 13 to 15 cloth with two feet of No. 10 at the tail. The flour from this reel goes to the baker's flour packer; that which drops through the No. 10 is sent to the middlings stone, while that which goes over the tail of the reel goes to purifier No. 4. We have now disposed of all the immediate products of the first five breaks, tracing them successively to the bran and shorts bins, to the baker's flour packer and to the middlings purifiers, a very small portion going to the middlings stone without going through the purifiers.

The middlings are handled as follows in the purifiers. From the No. 1 machine, which takes the middlings from the fifth break, the tailings go to the shorts bin, the middlings which are sufficiently well purified go to the middlings stone, while those from near the tail of the machine which contain a little germ and bran specks go to the second germ rolls, these being a pair of smooth rolls which flatten out the germ and crush the middlings, loosening adhering particles from the bran specks. From the second germ rolls the material goes to a reel, where it is separated into flour which goes into the baker's grade, fine middlings which are returned to the second germ rolls at once, some still coarser which go to a pair of finely corrugated iron rolls for red dog, and what goes over the tail of the reel goes to the shorts bin. The No. 2 purifier takes the coarse middlings from the tail of the first or chop reel as already stated. The tailings from this machine go to the shorts bin, some few middlings from next the tail of the machine are returned to the head of the same machine, while the remainder are sent to the first germ rolls. The reason for returning is more to enable the miller to keep a regular feed on the purifiers than otherwise. The No. 3 purifier takes the middlings from the 0 cloth on the chop reel. From purifier No. 3 they drop to purifier No. 5. A small portion that are not sufficiently well purified are returned to the head of No. 3, while those from the head of the machine, which are well purified, are sent to the middlings stones. The remainder, which contain a great deal of the germ, are taken to the first germ rolls, in passing which they are crushed lightly to flatten the germ without making any more flour than necessary. The No. 4 purifier takes the middlings from No. 2 and also from No. 5 cloth on the chop reel and from the No. 10 on the tail of the baker's reel. The middlings from the head of this machine go to the middlings stones, and the remainder to purifier No. 6. The tailings from Nos. 3, 4, 5, and 6 go to the red dog rolls. A small portion not sufficiently well purified are returned from No. 6 to the head of No. 4, while the cleaned middlings go to the middlings stones.

The portions of the material which have not been traced either to the baker's flour or the bran and shorts bins are the middlings which have gone to the middlings stones, the germy middlings which have gone to the first germ rolls, and the tailings from purifiers Nos. 3, 4, 5, and 6, and some little stuff not quite poor enough for shorts from the reel following the second germ rolls. Taking these _seriatim_: the middlings after passing through the middlings stones, go to the first patent reel covered with eleven feet of No. 13 and four feet of No. 8. The flour from the head of the reel goes to the patent packer, that from the remainder of the reel is dropped to another reel, while the tailings go to the No. 4 purifier. The lower patent reel is clothed with No. 14 and two feet of No. 10 cloth; from the head of the reel the flour goes to the patent packer, the remainder that passes through the No. 10 cloth which will not do to go into the patent, being returned to the middlings stones, while the tailings are sent to the No. 4 purifier.

The germ middlings, after being slightly crushed as before stated, are sent to a reel covered with five feet of No. 13 cloth, five feet of No. 14, and the balance with cloth varying in coarseness from No. 7 to No. 00. The flour from this reel goes into the patent, the tailings to the red dog rolls, the middlings from next the tail of the reel which still contain some germ to the second germ rolls, while the middlings which are free from germ go to the middlings stones.

The tailings from purifiers 3, 4, 5, and 6, the material from the reel following the second germ rolls, which is too good for shorts, but not good enough to be returned into middlings again, and the tailings from the reel following the first germ rolls are sent to the red dog rolls, which, as I have stated, are finely corrugated. Following these rolls is the red dog reel. The flour goes to the red dog bin, the tailings to the shorts bin, while some stuff intermediate between the two, not fine enough for the flour but too good for shorts, is returned to the red dog rolls.