The clean tomatoes should be conveyed to the steaming tanks and
subjected to steam heat until the skins burst and the meat softens.
After a short heating the tomatoes should be run through a “cyclone”
where the skins, seeds, etc., are removed and they are rubbed to a
pulp. To remove very small particles and fiber, the pulp may be run
through a sieving machine at once; or, if ketchup of the smoothest
possible kind is to be made, this procedure should be delayed until
after the cooking. The pulp is collected in a receiving vat, and
only such an amount should be provided in advance as will keep the
kettles full, as it is better to stop the tomatoes before going to
the washer than to have the pulp stand for some hours. In common
practice, however, the pulp is either sent to the cooker at once, or
it is allowed to stand and partially separate. If tall casks are used
for this separation the solids will rise to the top and the clear
watery portion is drawn off at the bottom, or the pulp may be strained
through cloth bags. The object of this separation is to secure greater
concentration of the solids, retain a brighter color, and shorten the
time of cooking.