[Illustration: Fig. 3.--A section of a kitchen showing the copper
cookers.]
The cooking may be done in copper kettles, as shown in figure 3, though
these are being superseded by enamel tanks containing silver-plated
coils in order to secure the brightest color. By using the latter the
discoloration due to the splashing of the contents against the walls of
the copper vessel is avoided, and economy of space is secured. Whole
or ground spices, or acetic acid or oil extracts of the spices may be
added to the pulp in such proportion as the particular brand demands.
The spices most used are cloves, cinnamon, mace, and cayenne pepper;
but paprika, pepper, mustard, cardamon, coriander, ginger, celery, and
allspice are used by some manufacturers. When whole spices are used,
it is the practice to suspend them in a cloth bag or a wire basket and
to take them out after boiling. They tend to darken the color of the
ketchup, a result considered undesirable by some. The ground spices
are used sparingly, with the exception of cayenne pepper. The acetic
acid extracts of spices are used because they are economical and give
a brighter red color than is obtained with the whole spice. The oil
extracts produce no discoloration, but they are the most expensive and
give an objectionable flavor. Hungarian sweet paprika is now quite
largely used and adds to the color as well as to the flavor. Sugar,
salt, and vinegar are added in such proportion as may be desired, and
in some brands onions and garlic are used.