As the consistency or body of ketchup is due chiefly to the tomato solids, the amount of evaporation necessary to secure ketchup of the desired consistency from a known volume of pulp measured at the boiling temperature and of known Brix or specific gravity can be determined from [Table 9, page 56]. For instance, if the volume of the boiling pulp is 800 gallons and the corrected Brix reading of the filtrate is 5.10, it is found from [Table 9] that it will be necessary to evaporate to 423 gallons to secure a ketchup of approximately the consistency of 1.040 pulp, to 374 gallons for a consistency comparable to 1.045 pulp and to 334 gallons for a consistency comparable to 1.050 pulp. This evaporation is carried out, of course, with the addition of the necessary ingredients for the making of ketchup. The amount of these ingredients can be varied in order to secure ketchup of the desired flavor.
After having once decided on the amount of ingredients to be used, the manufacture may be standardized. Supposing for instance on evaporating 800 gallons of partly concentrated pulp of Brix of filtrate (5.10) to approximately 334 gallons (calculated from the 1.050 column in [Table 9]) it has been found that the use of 301 pounds of sugar, 26.7 gallons of 100 grain vinegar, 66.8 pounds of salt and 50.2 pounds of onions together with spices gives ketchup of the flavor desired. Dividing the amount of each ingredient by 334, it is found that each gallon of finished ketchup contains .9 pound of added sugar, .2 pound of salt, .15 pound of onions, and about 10 ounces of vinegar. After having determined the amount of each ingredient per gallon of finished ketchup, it is easy to make a table giving the amount of ingredients necessary for a given volume of cyclone juice or concentrated pulp of any gravity. In [Table 11] such calculations are made. This table is based on securing a ketchup having the consistency of 1.050 pulp and starting with 800 gallons of boiling pulp of specific gravity 1.0220 (Brix reading of filtrate 5.10). Some manufacturers may desire to base the amount of ingredients on 100 gallons or multiple of 100 gallons of finished ketchup. This may be done by first making out a table similar to 9 and then calculating the amount of pulp and other ingredients for 100 gallons of ketchup. This would, however, involve considerable work as unless the pulp used had a constant specific gravity, a calculation of the quantity of each ingredient would have to be made for the volume of pulp for each batch.
Table 11.—Manufacture of Ketchup. Quantity of Constituents to be Added to 800 Gallons of Boiling, Partly Concentrated Pulp
| Specific gravity of pulp at 68° F. | Filtrate from pulp | Volume of finished ketchup | Added constituents | ||||
| Degrees Brix at 68° F. | Specific gravity at 68° F. | Sugar | 100-grain vinegar | Salt | Onions | ||
| _Gals._ | _Lbs._ | _Gals._ | _Lbs._ | _Lbs._ | |||
| 1.0154 | 3.50 | 1.0137 | 226.0 | 203 | 18.1 | 45.2 | 33.0 |
| 1.0158 | 3.60 | 1.0141 | 232.0 | 209 | 18.5 | 46.4 | 34.8 |
| 1.0162 | 3.70 | 1.0145 | 239.0 | 215 | 19.1 | 47.8 | 35.9 |
| 1.0166 | 3.80 | 1.0149 | 245.0 | 221 | 19.6 | 49.0 | 36.8 |
| 1.0170 | 3.90 | 1.0153 | 252.0 | 227 | 20.2 | 50.2 | 37.8 |
| 1.0174 | 4.00 | 1.0157 | 258.0 | 232 | 20.6 | 51.8 | 38.7 |
| 1.0178 | 4.10 | 1.0161 | 265.0 | 239 | 21.2 | 53.0 | 39.8 |
| 1.0182 | 4.20 | 1.0165 | 272.0 | 245 | 21.7 | 54.4 | 40.8 |
| 1.0186 | 4.30 | 1.0169 | 278.0 | 250 | 22.2 | 55.6 | 41.7 |
| 1.0190 | 4.40 | 1.0173 | 285.0 | 257 | 22.8 | 57.0 | 42.8 |
| 1.0194 | 4.50 | 1.0177 | 292.0 | 263 | 23.4 | 58.4 | 43.8 |
| 1.0199 | 4.60 | 1.0181 | 299.0 | 269 | 23.9 | 59.8 | 44.9 |
| 1.0202 | 4.70 | 1.0185 | 306.0 | 275 | 24.5 | 61.2 | 45.9 |
| 1.0206 | 4.80 | 1.0189 | 313.0 | 282 | 25.0 | 62.6 | 47.0 |
| 1.0211 | 4.90 | 1.0193 | 320.0 | 288 | 25.6 | 64.0 | 48.0 |
| 1.0216 | 5.00 | 1.0197 | 327.0 | 294 | 26.2 | 65.4 | 49.1 |
| 1.0220 | 5.10 | 1.0201 | 334.0 | 301 | 26.7 | 66.8 | 50.2 |
| 1.0224 | 5.20 | 1.0205 | 341.0 | 307 | 27.3 | 68.2 | 51.2 |
| 1.0228 | 5.30 | 1.0209 | 347.0 | 312 | 27.8 | 69.4 | 52.1 |
| 1.0232 | 5.40 | 1.0213 | 354.0 | 319 | 28.3 | 70.8 | 53.2 |
| 1.0236 | 5.50 | 1.0217 | 361.0 | 324 | 28.9 | 72.2 | 54.2 |
| 1.0240 | 5.60 | 1.0221 | 368.0 | 331 | 29.4 | 73.6 | 55.2 |
| 1.0244 | 5.70 | 1.0225 | 374.0 | 337 | 29.9 | 74.8 | 56.2 |
| 1.0249 | 5.80 | 1.0229 | 381.0 | 343 | 30.5 | 76.2 | 57.2 |
| 1.0253 | 5.90 | 1.0233 | 388.0 | 349 | 31.0 | 77.6 | 58.2 |
| 1.0257 | 6.00 | 1.0237 | 395.0 | 356 | 31.6 | 79.0 | 59.3 |
| 1.0261 | 6.10 | 1.0241 | 402.0 | 362 | 32.1 | 80.4 | 60.4 |
| 1.0266 | 6.20 | 1.0245 | 409.0 | 368 | 32.7 | 81.8 | 61.4 |
| 1.0271 | 6.30 | 1.0249 | 416.0 | 374 | 33.3 | 83.2 | 62.5 |
| 1.0275 | 6.40 | 1.0253 | 422.0 | 380 | 33.8 | 84.4 | 63.4 |
| 1.0279 | 6.50 | 1.0257 | 429.0 | 386 | 34.3 | 85.8 | 64.4 |
| 1.0283 | 6.60 | 1.0261 | 436.0 | 392 | 34.9 | 87.2 | 65.4 |
| 1.0287 | 6.70 | 1.0265 | 443.0 | 399 | 35.4 | 88.6 | 66.5 |
| 1.0291 | 6.80 | 1.0270 | 450.0 | 405 | 36.0 | 90.0 | 67.5 |
| 1.0295 | 6.90 | 1.0274 | 457.0 | 411 | 36.6 | 91.4 | 68.6 |
| 1.0299 | 7.00 | 1.0278 | 464.0 | 418 | 37.1 | 92.8 | 69.6 |
| 1.0304 | 7.10 | 1.0282 | 471.0 | 424 | 37.7 | 94.2 | 70.7 |
| 1.0309 | 7.20 | 1.0286 | 478.0 | 430 | 38.2 | 95.7 | 71.8 |
| 1.0313 | 7.30 | 1.0290 | 485.0 | 437 | 38.8 | 97.1 | 72.8 |
| 1.0318 | 7.40 | 1.0294 | 492.0 | 443 | 39.4 | 98.5 | 73.8 |
| 1.0322 | 7.50 | 1.0298 | 499.0 | 449 | 39.9 | 99.9 | 74.9 |
| 1.0326 | 7.60 | 1.0302 | 506.0 | 455 | 40.5 | 101.3 | 76.0 |
| 1.0330 | 7.70 | 1.0306 | 513.0 | 462 | 41.1 | 102.7 | 77.0 |
| 1.0335 | 7.80 | 1.0310 | 521.0 | 469 | 41.7 | 104.2 | 78.2 |
| 1.0339 | 7.90 | 1.0315 | 529.0 | 476 | 42.3 | 105.8 | 79.4 |
| 1.0343 | 8.00 | 1.0319 | 536.0 | 482 | 42.9 | 107.2 | 80.4 |
| 1.0347 | 8.10 | 1.0323 | 543.0 | 489 | 43.5 | 108.6 | 81.5 |
| 1.0352 | 8.20 | 1.0327 | 550.0 | 495 | 44.0 | 110.0 | 82.6 |
| 1.0356 | 8.30 | 1.0331 | 557.0 | 501 | 44.5 | 111.4 | 83.6 |
| 1.0361 | 8.40 | 1.0335 | 564.0 | 508 | 45.1 | 112.8 | 84.7 |
| 1.0365 | 8.50 | 1.0339 | 571.0 | 514 | 45.7 | 114.2 | 85.7 |
| 1.0369 | 8.60 | 1.0343 | 578.0 | 520 | 46.2 | 115.6 | 86.8 |
| 1.0374 | 8.70 | 1.0348 | 585.0 | 527 | 46.8 | 117.0 | 87.8 |
| 1.0379 | 8.80 | 1.0352 | 592.0 | 533 | 47.4 | 118.4 | 88.8 |
| 1.0383 | 8.90 | 1.0356 | 600.0 | 540 | 48.0 | 119.0 | 90.0 |
The use of [Table 11] gives a ketchup of medium concentration. Using this as a basis the manufacturer can decide the extent to which he should evaporate to secure a ketchup of the consistency desired and modify the table accordingly.
Final concentration of the ketchup is controlled in the same manner as for pulp, either by a gauged tank or by specific gravity determination. If we start, therefore, with a given volume of partially concentrated cyclone juice and determine the solids present, we can in every case quickly ascertain from the appropriate table the number of gallons of finished product we should obtain, and the gauge stick or attached gauge glass will indicate when to stop evaporation in the tank. One advantage of measuring the original volume at the boiling temperature is that no temperature corrections are necessary, as both the initial and final temperature measurements are approximately the same.
The final concentration may be controlled, as stated above, by determining the specific gravity of the finished product by one of the methods given under pulp (see page 33 and following). The determination of specific gravity at this point will probably give more accurate results than the use of a gauge stick, and is to be recommended for use with the finished product, provided the added constituents have been standardized. The method described on page 42 for determining the specific gravity of hot tomato pulp, may be used for obtaining the per cent of solids in the boiling cyclone juice in place of the Brix spindle reading on the filtrate.
[Table 11] for controlling the concentration of finished ketchup is based on the idea that there shall be a definite volume of partly concentrated pulp in the tank when the inflow of cyclone juice is stopped and the sample is taken for analysis. In this respect, this method of controlling the concentration of ketchup varies from the method described on page 54 for the control of the concentration of tomato pulp. It is sometimes convenient to secure this definite volume by filling the tank to a greater height than is desired and evaporating until the desired volume is secured. When this point is reached the sample of pulp is taken for specific gravity and steam is again turned on the tank.
The Abbé refractometer may also be used for controlling the final concentration of the ketchup. This provides a very simple and quick method for determining the percentage of solids. It requires but a few drops of the filtered liquor from the ketchup to make the determination. The reading may be taken and the calculation made in one or two minutes’ time by use of Tables 13 and 14.
The table for calculating the solids from the refractometer reading is Geerlig’s table for dry substance in sugar-house products, and is taken from the Methods of the Association of Official Agricultural Chemists, 1919. The entire table is not given but only the range over which it might possibly be desired to use it in the control of the manufacture of ketchup.