Practically all of the tomato products made in this country are cooked in an open kettle under atmospheric pressure—either a copper-jacketed kettle, or a tank with a closed coil. The vacuum pan is used, however, in several plants, and makes a very high grade product—a better product as a rule than can be made by condensing under atmospheric pressure. When tomato juice is condensed in vacuum it boils at anywhere from 54 degrees F. to 175 degrees F., depending upon the degree of vacuum obtained. At sea level, under atmospheric pressure, it boils at 212 degrees F. By employing a low temperature, and condensing rapidly, which can be done in the vacuum pan, the natural bright red color of the tomatoes is affected very little by the cooking. High temperatures and continued boiling are the agents which destroy tomato color as well as flavor. The vacuum pan produces a pulp of not only fine color, but of very fine flavor. The reason the vacuum method is not used more frequently than it is is undoubtedly due to the difficulty in getting the vacuum equipment, and also to the expense of the equipment when it can be obtained. Types of Open Kettles The open kettle method produces a very satisfactory product when the proper precautions are taken, and if the cooking and subsequent processes are carried out intelligently, the finished product compares very favorably with that which is condensed in vacuum. The types of kettles in most common use are the copper jacketed kettle, the glass-lined tank with closed copper coil, and the cypress tank with closed copper coil. All of these give good results where the jacket or coil is properly constructed, the steam trap is of the right type and takes care of all of the condensation without allowing it to back up into the coil, and the kettle has a good head of steam so that a vigorous boil can be maintained throughout the cooking. Steam Pressure If the steam pressure at the boiler is kept above 75 lbs., and too much is not lost by radiation from uncovered pipes, and by leaks at poorly packed flanges, etc., there should be no difficulty in maintaining a vigorous boil. The evaporation should be so rapid that the vaporizing steam will burn the hand, even if placed over the kettle for a second. If you can hold your hand over a kettle of boiling pulp, even for a few seconds, you can be sure that you are not getting a proper boil. A pressure of 100 lbs. is, of course, to be preferred to 75, as it will effect a quicker condensation, however there is not a large percentage of boilers in tomato pulp plants that are permitted to carry as much as 100 lbs.