The evaporation should be as rapid as possible. The operation of the kettles in such a way that the pulp burns on the kettles or on the coils damages the flavor of the product and impairs its color. The pulp should be cooled promptly after processing, or if that is not practicable should be stacked loosely so that the cans will have ample ventilation until they are entirely cooled. Pulp packed in five-gallon cans is rarely processed. It should, however, be filled into the cans at a temperature of at least 180° F. It is best to give pulp in No. 10 and smaller size cans a short process in boiling water. With pulp filled at 180° F., ten or fifteen minutes is a sufficient cook. Pulp filled at lower temperatures or which is allowed to partially cool before processing requires a longer process. In order to protect the color it is best to water cool No. 10 cans of pulp after processing. Pulp in cans of any size should not be stacked solid while it is still hot. The metal of the can has a bleaching action on the pulp and this is greatly increased if the pulp is stacked hot or stored in a hot warehouse. If stacked while excessively hot, stack-burning may occur with consequent darkening of the pulp. As indicated above, there is a considerable difference of opinion among successful manufacturers of pulp regarding the details of manufacture necessary to secure the best results. It is probable that different conditions call for different methods of operation. At any rate, all successful manufacturers are agreed that the color of the pulp is an important index to its quality and greatly influences its commercial value. The flavor of pulp is also an important criterion and is considered by many buyers in forming an estimate of the value of pulp. A scorched taste or a flat flavor show that the manufacture of the pulp was not adequately controlled and impairs the commercial value of the product. Color and flavor commonly go together. The same manufacturing methods which yield a product of high color are likely to give a product of superior flavor. DISCARDING TOMATO JUICE It was formerly customary, and is still the practice of some manufacturers of tomato pulp, to discard a portion of the juice of the tomatoes. Some manufacturers, especially in the preparation of pulp from tomato trimmings, allow the trimmings to pass over a colander and thus separate the free juice, which is discarded. Others allow the product of the cyclone to stand for a time in tanks and then discard the clear juice which settles in the bottom of the tanks. Both practices are wasteful and have generally been discontinued. Some still adhere to one or both, however, and it was thought best to make the matter the subject of study.