Part 7

In using this method, the manner in which the cyclone juice is prepared is immaterial. The tomatoes may be broken by steam or mechanical breaker and may be cycloned hot or cold. The steam may be turned into the coils as soon as they are covered and the cyclone juice may run into the evaporating tank until the tank is filled.

Finally, when the last of the cyclone juice is added and the contents of the tank are boiling vigorously, the steam is momentarily turned off. The volume is then determined by means of a gauge stick and a sample is withdrawn, filtered and the specific gravity or degrees Brix determined as described on page 50. The extent to which evaporation must be continued to secure pulp of the desired specific gravity is determined by Table 9.

This table gives in the first four columns the specific gravity of the partially concentrated pulp taken from the evaporating tank, the per cent of solids of the same, the specific gravity of the filtrate and the Brix reading of the filtrate. In order to use the tables, it is only necessary to make use of one of these columns.

This method of operation can be simplified and more accurate results obtained by equipping each evaporating tank with a one-inch gage glass extending the full height of the tank. The gage glass should be open at the top and connected with the bottom of the tank by a pipe equipped with a valve. Before the tank is filled with cyclone juice the valve is turned off and the gage glass filled with water. Steam is turned on as soon as the pipes are covered and the foam is “broken” quickly without trouble that was experienced in heating the tank filled with cool pulp. The heat is continued while the tank is filled to the desired height with the pulp. The steam is then momentarily turned off and the valve at the top of the gage glass opened to permit the water in the gage glass to equalize in height with the partly concentrated pulp within the tank. The height of water in the gage glass is read by a scale attached, the sample of the pulp taken for examination and the steam again turned on.

There is ample time to determine the specific gravity of the sample of partly concentrated pulp and from its volume as obtained by the gage glass to calculate the volume to which the pulp should be evaporated to secure the desired specific gravity in the finished product. The specific gravity of the sample may be taken by any of the methods described in the chapter on “Determination of specific gravity.” More accurate results can be obtained by pouring the sample of pulp as soon as it is taken into a large loosely stoppered flask and holding the flask with constant agitation in a tub of ice water until it is brought to about the temperature of the room.

Having determined the volume (when heated to the boiling point) of a batch of cyclone juice or of pulp at any stage of its manufacture and its specific gravity (at 68° F.), each of the last five columns of the table gives a factor by which the volume of the partially evaporated pulp may be multiplied to determine the volume of pulp of the specific gravity given at the top of the column. Since both measurements are taken at the boiling point the question of temperature need not be considered.

Table 8.—_Corrections for Specific Gravity and Brix_[19] _Readings at Different Temperatures to 68 Degrees F._ (_20 Degrees C._)

Corrections to be subtracted from specific gravity or degrees Brix.

===============+============= Temperature | Corrections -------+-------+-------+----- Deg. F.|Deg. C.|Sp. Gr.|Brix. -------+-------+-------+----- 50 | 10.0 | .0017 | .38 51 | 10.6 | .0016 | .36 52 | 11.1 | .0016 | .35 53 | 11.7 | .0015 | .33 54 | 12.2 | .0014 | .31 | | | 55 | 12.8 | .0014 | .30 56 | 13.3 | .0013 | .28 57 | 13.9 | .0012 | .26 58 | 14.4 | .0011 | .24 | | | 59 | 15.0 | .0010 | .22 60 | 15.6 | .0009 | .20 61 | 16.1 | .0009 | .18 62 | 16.7 | .0008 | .16 63 | 17.2 | .0007 | .13 | | | 64 | 17.8 | .0006 | .11 65 | 18.3 | .0004 | .08 66 | 18.9 | .0003 | .05 67 | 19.4 | .0002 | .03

69 | 20.6 | .0002 | .03 70 | 21.1 | .0003 | .05 71 | 21.7 | .0004 | .08 72 | 22.2 | .0006 | .11 73 | 22.8 | .0007 | .15 | | | 74 | 23.3 | .0009 | .18 75 | 23.9 | .0011 | .21 76 | 24.4 | .0012 | .24 77 | 25.0 | .0013 | .28 78 | 25.6 | .0015 | .32 | | | 79 | 26.1 | .0017 | .35 80 | 26.7 | .0018 | .39 81 | 27.2 | .0019 | .42 82 | 27.8 | .0021 | .46 83 | 28.3 | .0023 | .49 | | | 84 | 28.9 | .0024 | .54 85 | 29.4 | .0026 | .58 86 | 30.0 | .0027 | .62 87 | 30.6 | .0029 | .66 88 | 31.1 | .0031 | .70 -------+-------+-------+----- [19] These temperature corrections are for a Brix instrument standardized for 20°C. There are Brix hydrometers on the market standardized for 17.5°C. Temperature corrections for a Brix hydrometer standardized at this temperature may be obtained by correcting to 20° by means of the above table (for instrument graduated at 20°C.) and adding to this corrected reading 0.12. For instance suppose the reading for a 17.5° instrument is 7.00 at 25°C. The correction from the above table will be .28 or a total of 7.28. Adding .12 to this gives a corrected reading of 7.40. If the reading is 7.00 at 15°C. the correction from the above table amounts to .22 (to be subtracted) giving 6.78. Adding 0.12 to this gives the corrected reading of 6.90.

TABLE 9.—_Equivalent Volumes of Pulp of Different Degrees of Concentration_

======================================================================== | | Factor by which to multiply volume of Tomato pulp | Filtrate | pulp of given specific gravity to | from pulp | ascertain volume of pulp with | | equivalent solid content and with | | specific gravity of --------+-------+--------+-------+-------+-------+-------+-------+------- Specific| Per |Specific|Degrees| | | | | gravity | cent |gravity | Brix | | | | | at |solids | at | at | 1.030 | 1.035 | 1.040 | 1.045 | 1.050 68° F. | | 68° F.| 68° F.| | | | | --------+-------+--------+-------+-------+-------+-------+-------+------- 1.0125 | 2.79 | 1.0108 | 2.78 | .384 | .326 | .283 | .249 | .223 1.0130 | 2.92 | 1.0113 | 2.89 | .402 | .342 | .296 | .261 | .234 1.0135 | 3.05 | 1.0118 | 3.02 | .420 | .357 | .310 | .273 | .244 1.0140 | 3.17 | 1.0123 | 3.14 | .437 | .372 | .323 | .285 | .255 1.0145 | 3.30 | 1.0128 | 3.27 | .455 | .388 | .336 | .297 | .265 | | | | | | | | 1.0150 | 3.42 | 1.0133 | 3.40 | .472 | .401 | .348 | .306 | .274 1.0155 | 3.54 | 1.0138 | 3.51 | .489 | .416 | .361 | .318 | .284 1.0160 | 3.67 | 1.0143 | 3.65 | .507 | .431 | .374 | .329 | .294 1.0165 | 3.79 | 1.0148 | 3.77 | .524 | .445 | .387 | .341 | .304 1.0170 | 3.92 | 1.0153 | 3.90 | .542 | .460 | .400 | .352 | .315 | | | | | | | | 1.0175 | 4.05 | 1.0158 | 4.03 | .560 | .476 | .413 | .364 | .325 1.0180 | 4.18 | 1.0163 | 4.15 | .579 | .491 | .426 | .375 | .335 1.0185 | 4.30 | 1.0168 | 4.28 | .596 | .506 | .440 | .387 | .346 1.0190 | 4.43 | 1.0173 | 4.40 | .614 | .521 | .452 | .399 | .356 1.0195 | 4.56 | 1.0178 | 4.53 | .632 | .537 | .466 | .410 | .367 | | | | | | | | 1.0200 | 4.68 | 1.0182 | 4.63 | .649 | .551 | .478 | .421 | .377 1.0205 | 4.81 | 1.0188 | 4.77 | .667 | .566 | .491 | .433 | .387 1.0210 | 4.93 | 1.0192 | 4.87 | .684 | .581 | .504 | .444 | .398 1.0215 | 5.05 | 1.0196 | 4.97 | .701 | .596 | .517 | .456 | .407 1.0220 | 5.17 | 1.0201 | 5.10 | .718 | .610 | .529 | .467 | .417 | | | | | | | | 1.0225 | 5.30 | 1.0206 | 5.22 | .737 | .625 | .543 | .479 | .428 1.0230 | 5.43 | 1.0211 | 5.35 | .755 | .641 | .556 | .490 | .438 1.0235 | 5.55 | 1.0216 | 5.47 | .772 | .656 | .569 | .502 | .448 1.0240 | 5.67 | 1.0220 | 5.57 | .789 | .671 | .582 | .513 | .459 1.0245 | 5.80 | 1.0226 | 5.72 | .808 | .686 | .595 | .525 | .469 | | | | | | | | 1.0250 | 5.92 | 1.0230 | 5.82 | .825 | .701 | .608 | .536 | .479 1.0255 | 6.04 | 1.0235 | 5.94 | .842 | .715 | .620 | .547 | .489 1.0260 | 6.16 | 1.0240 | 6.07 | .859 | .729 | .633 | .558 | .499 1.0265 | 6.28 | 1.0244 | 6.17 | .876 | .744 | .646 | .569 | .509 1.0270 | 6.40 | 1.0249 | 6.29 | .894 | .759 | .658 | .580 | .519 | | | | | | | | 1.0275 | 6.53 | 1.0254 | 6.43 | .912 | .775 | .672 | .592 | .529 1.0280 | 6.65 | 1.0258 | 6.53 | .930 | .789 | .685 | .604 | .539 1.0285 | 6.77 | 1.0263 | 6.65 | .947 | .804 | .697 | .615 | .549 1.0290 | 6.90 | 1.0268 | 6.78 | .965 | .819 | .711 | .626 | .560 1.0295 | 7.02 | 1.0273 | 6.90 | .983 | .834 | .724 | .638 | .570 | | | | | | | | 1.0300 | 7.14 | 1.0278 | 7.03 | 1.000 | .849 | .737 | .649 | .580 1.0305 | 7.26 | 1.0282 | 7.13 | 1.017 | .864 | .749 | .660 | .590 1.0310 | 7.38 | 1.0287 | 7.23 | 1.035 | .878 | .762 | .672 | .600 1.0315 | 7.50 | 1.0292 | 7.35 | 1.052 | .893 | .775 | .683 | .610 1.0320 | 7.63 | 1.0296 | 7.45 | 1.071 | .908 | .788 | .695 | .621 | | | | | | | | 1.0325 | 7.75 | 1.0301 | 7.58 | 1.088 | .924 | .802 | .706 | .631 1.0330 | 7.88 | 1.0306 | 7.70 | 1.107 | .939 | .815 | .718 | .642 1.0335 | 8.00 | 1.0310 | 7.80 | 1.124 | .954 | .828 | .730 | .652 1.0340 | 8.12 | 1.0315 | 7.93 | 1.142 | .970 | .842 | .742 | .663 1.0345 | 8.25 | 1.0320 | 8.05 | 1.160 | .985 | .855 | .753 | .673 | | | | | | | | 1.0350 | 8.37 | 1.0325 | 8.16 | 1.178 | 1.000 | .868 | .765 | .684 1.0355 | 8.50 | 1.0330 | 8.27 | 1.197 | 1.016 | .882 | .777 | .695 1.0360 | 8.62 | 1.0334 | 8.37 | 1.214 | 1.031 | .895 | .788 | .705 1.0365 | 8.74 | 1.0339 | 8.50 | 1.232 | 1.046 | .907 | .800 | .715 1.0370 | 8.86 | 1.0344 | 8.63 | 1.249 | 1.061 | .920 | .811 | .725 | | | | | | | | 1.0375 | 8.98 | 1.0349 | 8.75 | 1.267 | 1.076 | .933 | .823 | .735 1.0380 | 9.10 | 1.0353 | 8.85 | 1.284 | 1.091 | .947 | .834 | .746 1.0385 | 9.23 | 1.0358 | 8.97 | 1.303 | 1.106 | .960 | .846 | .756 1.0390 | 9.35 | 1.0363 | 9.07 | 1.321 | 1.122 | .974 | .858 | .767 1.0395 | 9.48 | 1.0368 | 9.20 | 1.340 | 1.138 | .987 | .870 | .778 | | | | | | | | 1.0400 | 9.60 | 1.0372 | 9.30 | 1.358 | 1.153 | 1.000 | .881 | .788 1.0405 | 9.73 | 1.0378 | 9.45 | 1.377 | 1.168 | 1.014 | .893 | .799 1.0410 | 9.85 | 1.0383 | 9.57 | 1.394 | 1.184 | 1.027 | .905 | .809 1.0415 | 9.97 | 1.0387 | 9.67 | 1.412 | 1.199 | 1.041 | .917 | .820 1.0420 | 10.10 | 1.0393 | 9.80 | 1.431 | 1.215 | 1.054 | .929 | .830 | | | | | | | | 1.0425 | 10.22 | 1.0397 | 9.90 | 1.449 | 1.230 | 1.067 | .941 | .841 1.0430 | 10.35 | 1.0402 | 10.03 | 1.468 | 1.246 | 1.081 | .953 | .851 1.0435 | 10.47 | 1.0406 | 10.13 | 1.486 | 1.261 | 1.094 | .964 | .862 1.0440 | 10.60 | 1.0411 | 10.25 | 1.505 | 1.277 | 1.108 | .976 | .873 1.0445 | 10.72 | 1.0416 | 10.36 | 1.523 | 1.293 | 1.122 | .988 | .884 | | | | | | | | 1.0450 | 10.84 | 1.0420 | 10.45 | 1.540 | 1.308 | 1.135 | 1.000 | .894 1.0455 | 10.96 | 1.0425 | 10.57 | 1.558 | 1.322 | 1.148 | 1.012 | .904 1.0460 | 11.08 | 1.0429 | 10.67 | 1.576 | 1.338 | 1.161 | 1.023 | .915 1.0465 | 11.20 | 1.0435 | 10.83 | 1.594 | 1.353 | 1.174 | 1.035 | .925 1.0470 | 11.33 | 1.0440 | 10.93 | 1.613 | 1.369 | 1.188 | 1.047 | .936 | | | | | | | | 1.0475 | 11.45 | 1.0445 | 11.05 | 1.631 | 1.384 | 1.201 | 1.059 | .946 1.0480 | 11.57 | 1.0449 | 11.15 | 1.649 | 1.400 | 1.215 | 1.071 | .957 1.0485 | 11.70 | 1.0454 | 11.27 | 1.668 | 1.416 | 1.229 | 1.083 | .968 1.0490 | 11.82 | 1.0459 | 11.40 | 1.686 | 1.432 | 1.243 | 1.095 | .979 1.0495 | 11.95 | 1.0465 | 11.53 | 1.705 | 1.449 | 1.256 | 1.107 | .990 | | | | | | | | 1.0500 | 12.07 | 1.0468 | 11.60 | 1.724 | 1.464 | 1.270 | 1.119 | 1.00 1.0505 | 12.20 | 1.0474 | 11.75 | 1.743 | 1.479 | 1.284 | 1.131 | 1.01 1.0510 | 12.32 | 1.0478 | 11.84 | 1.761 | 1.495 | 1.298 | 1.144 | 1.02 1.0515 | 12.45 | 1.0482 | 11.93 | 1.780 | 1.511 | 1.311 | 1.156 | 1.03 1.0520 | 12.57 | 1.0488 | 12.07 | 1.797 | 1.526 | 1.325 | 1.167 | 1.04 | | | | | | | | 1.0525 | 12.69 | 1.0492 | 12.17 | 1.816 | 1.542 | 1.338 | 1.179 | 1.05 1.0530 | 12.81 | 1.0497 | 12.30 | 1.834 | 1.557 | 1.351 | 1.191 | 1.06 1.0535 | 12.93 | 1.0502 | 12.40 | 1.852 | 1.572 | 1.364 | 1.203 | 1.07 1.0540 | 13.05 | 1.0506 | 12.50 | 1.870 | 1.588 | 1.378 | 1.215 | 1.08 1.0545 | 13.18 | 1.0512 | 12.65 | 1.890 | 1.604 | 1.392 | 1.227 | 1.09 | | | | | | | | 1.0550 | 13.30 | 1.0516 | 12.74 | 1.908 | 1.620 | 1.405 | 1.239 | 1.10 1.0555 | 13.42 | 1.0520 | 12.83 | 1.926 | 1.635 | 1.419 | 1.250 | 1.11 1.0560 | 13.55 | 1.0525 | 12.95 | 1.945 | 1.651 | 1.433 | 1.263 | 1.12 1.0565 | 13.67 | 1.0529 | 13.05 | 1.964 | 1.667 | 1.447 | 1.275 | 1.14 1.0570 | 13.80 | 1.0534 | 13.16 | 1.983 | 1.684 | 1.461 | 1.288 | 1.15 --------+-------+--------+-------+-------+-------+-------+-------+-----

TABLE 10.—_Specific Gravity and Solids of Tomato Pulp_[20]

=========+========== Specific | Per cent gravity | solids at 68° F.|_in vacuo_ |at 70° C. ---------+---------- 1.0145 | 3.30 1.0150 | 3.42 1.0155 | 3.55 1.0160 | 3.67 1.0165 | 3.80 | 1.0170 | 3.92 1.0175 | 4.05 1.0180 | 4.18 1.0185 | 4.30 1.0190 | 4.43 | 1.0195 | 4.56 1.0200 | 4.68 1.0205 | 4.81 1.0210 | 4.93 1.0215 | 5.05 | 1.0220 | 5.17 1.0225 | 5.30 1.0230 | 5.43 1.0235 | 5.55 1.0240 | 5.67 | 1.0245 | 5.80 1.0250 | 5.92 1.0255 | 6.04 1.0260 | 6.16 1.0265 | 6.28 | 1.0270 | 6.40 1.0275 | 6.53 1.0280 | 6.65 1.0285 | 6.77 1.0290 | 6.90 | 1.0295 | 7.02 1.0300 | 7.14 1.0305 | 7.26 1.0310 | 7.38 1.0315 | 7.50 | 1.0320 | 7.63 1.0325 | 7.75 1.0330 | 7.88 1.0335 | 8.00 1.0340 | 8.12 | 1.0345 | 8.25 1.0350 | 8.37 1.0355 | 8.50 1.0360 | 8.62 1.0365 | 8.74 | 1.0370 | 8.86 1.0375 | 8.98 1.0380 | 9.10 1.0385 | 9.23 1.0390 | 9.35 | 1.0395 | 9.48 1.0400 | 9.60 1.0405 | 9.73 1.0410 | 9.85 1.0415 | 9.97 | 1.0420 | 10.10 1.0425 | 10.22 1.0430 | 10.35 1.0435 | 10.47 1.0440 | 10.60 | 1.0445 | 10.72 1.0450 | 10.84 1.0455 | 10.96 1.0460 | 11.08 1.0465 | 11.20 | 1.0470 | 11.33 1.0475 | 11.45 1.0480 | 11.57 1.0485 | 11.70 1.0490 | 11.82 | 1.0495 | 11.95 1.0500 | 12.07 1.0505 | 12.20 1.0510 | 12.32 1.0515 | 12.45 | 1.0520 | 12.57 1.0525 | 12.69 1.0530 | 12.81 1.0535 | 12.93 1.0540 | 13.05 | 1.0545 | 13.18 1.0550 | 13.30 1.0555 | 13.42 1.0560 | 13.55 1.0565 | 13.67 | 1.0570 | 13.80 1.0575 | 13.92 1.0580 | 14.05 1.0585 | 14.17 1.0590 | 14.29 | 1.0595 | 14.42 1.0600 | 14.54 1.0605 | 14.67 1.0610 | 14.79 1.0620 | 15.03 | 1.0630 | 15.27 1.0640 | 15.52 1.0650 | 15.77 1.0660 | 16.02 1.0670 | 16.27 | 1.0680 | 16.52 1.0690 | 16.77 1.0700 | 17.02 1.0710 | 17.27 1.0720 | 17.51 | 1.0730 | 17.76 1.0740 | 18.00 1.0750 | 18.25 1.0760 | 18.50 1.0770 | 18.75 | 1.0780 | 18.99 1.0790 | 19.24 1.0800 | 19.48 1.0810 | 19.72 1.0820 | 19.97 | 1.0830 | 20.22 1.0840 | 20.47 1.0850 | 20.72 1.0860 | 20.96 1.0870 | 21.21 | 1.0880 | 21.46 1.0890 | 21.70 1.0900 | 21.95 1.0910 | 22.20 1.0920 | 22.45 | 1.0930 | 22.70 1.0940 | 22.94 1.0950 | 23.18 1.0960 | 23.43 1.0970 | 23.68 | 1.0980 | 23.93 1.0990 | 24.18 1.1000 | 24.43 1.1010 | 24.67 1.1020 | 24.92 | 1.1030 | 25.18 1.1040 | 25.42 1.1050 | 25.67 1.1060 | 25.91 1.1070 | 26.16 ---------+---------- [20] This table gives the per cent of total solids contained by pulp of different specific gravities varying from unconcentrated pulp as it comes from the cyclone to the highly concentrated product.

Illustration: Suppose that when the cyclone juice is all added to the tank the contents of which are vigorously boiling so that they are doubtless of uniform composition, the volume is found by the gauge stick to be 815 gallons. A sample of this partially evaporated pulp is withdrawn and filtered and the filtrate is found to have a Brix reading of 6.90. Let us suppose that the product is to be evaporated to a pulp having a specific gravity of 1.035 and the operator desires to know at what point to turn off the steam. By referring to Table 9 in the column headed by the figure 1.035, we find opposite the Brix reading 6.90 the factor .834. Multiplying the volume of the pulp (815 gallons) by this factor, we obtain 680 gallons. It follows, therefore, that the steam should be turned off when the evaporation has reached such a point that the gauge stick shows the volume of pulp to be 680 gallons.

Table 9 may be used in the same way for calculating the volume of any pulp, hot or cold, of any specified specific gravity equivalent to a certain volume of pulp of any other stated specific gravity when held at the same temperature. For instance, the illustration given above serves equally well to illustrate how the relative value of two finished pulps of different specific gravities may be calculated. It also shows directly the relative value (based on tomato solids alone) of the same volume of two pulps of different gravity.

Illustration: Suppose a shipment contains 1,000 cases of No. 10 cans of pulp thought to have a specific gravity of 1.040 but found on examination to have a specific gravity of 1.0365. What is the value of the pulp in comparison with pulp of specific gravity of 1.040? Turning in Table 9 to the figure 1.0365 in the left-hand column we follow the horizontal line containing that figure to the column headed by specific gravity 1.040. Here we find that .907 is the factor by which to multiply the volume of pulp of a specific gravity 1.0365 to obtain the equivalent volume of pulp of specific gravity 1.040. The answer to our question therefore is 1000 × .907 = 907. In other words pulp of a gravity of 1.0365 judged by the tomato solids it contains, has 90.7 per cent of the value of pulp of the gravity of 1.040.

Table 9 is based on the results obtained from a series of samples of whole tomato pulp and cyclone juice varying in specific gravity from 1.02 to 1.05. The table was extended by calculation to give corresponding values for more dilute cyclone juices and more concentrated products. The lower portion of the table has been repeatedly confirmed by results obtained in the examination of cyclone juice and pulp, but the figures in the higher portion of the table are based on calculation from lower concentrations.

This table is only applicable to pulp to which no other substance, such as salt, has been added. Salt if present to the extent of more than 0.25 per cent can be recognized by the taste. The amount of salt, when any has been added, may be determined by the method given on page 33 and the specific gravity corrected by subtracting from the apparent specific gravity 0.007 for each per cent of salt present. This gives the specific gravity of the salt-free pulp and the corresponding per cent of solids may be obtained from Table 9.

TOMATO KETCHUP

Ketchup is defined in the Federal food standards as the clean, sound product made from properly prepared pulp of clean, sound, fresh, ripe tomatoes, with spices, and with or without sugar and vinegar.

The solid matter, or total solids, in ketchup varies from less than 12 per cent to over 37 per cent. This means that the product varies from a substance having barely sufficient tomato added to give color and taste, to a rich, heavy tomato ketchup. The variation of total solids in any one brand is, of course, less, but large differences are not unusual. Three bottles of one brand showed a solids content varying from 12 per cent to 16 per cent, and seven of another brand varied from 32 per cent to 37.2 per cent.

The amount of solids in a non-preservative ketchup should be not materially less than 28 per cent. It is necessary to have a rather high solid content for ketchup of this kind, so that it may keep after being opened on the consumer’s table.

The variation in the insoluble solids is comparable to that in the total solids. The values for a number of samples examined in this laboratory ranged from .9 per cent to 2.3 per cent. As the insoluble solids come from the tomato pulp the amount of insoluble solids is to that extent an indication of the amount of tomato pulp used in the manufacture of the ketchup from whole tomato pulp. The consistency of the ketchup is dependent chiefly on the amount of insoluble tomato solids present.