None of the ingredients should be added until all of the tomato juice for the batch is in the kettle, with the exception of the bag of spices. It is usually not considered advisable to cook batches of catsup of over 300 gallons when finished. I have cooked as much as 400 gallons at a time, but it requires quite a long cook to complete the condensation unless the tank has a large surface for evaporation and a coil with a very large cooking capacity, and a high steam pressure is available. Amount of Tomatoes In discussing the proper amounts of the various ingredients to use, a batch of finished catsup of 100 gallons in volume, when measured hot, will be taken as the basis throughout this chapter. The amount of tomatoes required to make 100 gallons of finished catsup varies according to the season of the year and the quality of the stock. If the tomatoes are watery, or contain so much rot that 25% or more must be cut away, that of course makes a big difference. If, on the other hand, the tomatoes are large and meaty, and contain scarcely any rot, a comparatively small amount of them are required. Taking tomatoes of average size, containing an average amount of solid matter, and from which 10% by weight of rotten material is sorted out, it is safe to figure on 37 bushels of tomatoes or 59⅝th bushel baskets for 100 gallons of finished catsup. Keeping Batches Uniform If the catsup batches are to be kept uniform in size throughout the season, as they should be, the quantity of tomatoes per batch will have to be changed slightly from time to time according to the amount of water they contain. The only safe way is to put a gauge on each cooking tank which marks the desired volume of catsup when cooked, and to vary the volume of tomato juice per batch to the extent which is indicated by the gauge. If the batches are running two inches low, the cook will know by a little experimenting just how much extra juice will be required per batch to make it right. Having all the batches come out exactly the same in size is important, both in preservative and non-preservative goods. In the former, the percentage of preservative cannot, of course, be kept uniform unless the batches are kept uniform in size. In non-preservative goods it is advisable to keep the percentage of acetic acid—that ingredient upon which the keeping quality chiefly depends—as nearly uniform as possible. Of course, if a batch runs large, the acetic acid percentage will be low, while if the batch runs small, the acetic acid percentage will be higher than necessary. The spicing will also be more uniform if the batches are uniform in size. Use of Spices in a Sack