require the packages to bear a label setting forth the fact
that alum is one of the ingredients; others require the baking powder
packages to bear a label naming all the ingredients of the powder.

200. Fillers.--All baking powders contain a filler of starch. This is
necessary to keep the materials from acting before the powder is used.
The amount of filler varies from 15 to 50 per cent; the least is found
in the tartrate powders and the most in the phosphate powders. The
amount of gas which a powder gives off regulates its value; it should
give off at least 1/8 of its weight.

201. Home-made Baking Powders.--Baking powders can be made at home for
about one half what they usually cost and they will give equal
satisfaction. The following will make a long-keeping powder: cream of
tartar, 8 ounces; baking soda, 4 ounces; corn starch, 3 ounces. For a
quick-acting powder use but one ounce of starch. The materials should be
thoroughly dry. Mix the soda and starch first by shaking well in a glass
or tin can. Add the cream of tartar last and shake again. Thorough
mixing is essential to good results. Cream of tartar is often
adulterated, but it can be obtained pure from a reliable druggist. To
insure baking powders remaining perfectly dry, they should always be
kept in glass or tin cans, never in paper.

CHAPTER XIII

VINEGAR, SPICES, AND CONDIMENTS

202. Vinegar.--Vinegar is a dilute solution of acetic acid produced by
fermentation, and contains, in addition to acetic acid, small amounts of
other materials in solution, as mineral matter and malic acid, according
to the material from which the vinegar was made. Unless otherwise
designated, vinegar in this country is generally considered to be made
from apples. Other substances, however, are used, as vinegar can be
manufactured from a variety of fermentable materials, as molasses,
glucose, malt, wine, and alcoholic beverages in general. The chemical
changes which take place in the production of vinegars are: (1)
inversion of the sugar, (2) conversion of the invert sugars into
alcohol, and (3) change of alcohol into acetic acid. All these chemical
changes are the result of ferment action. The various invert ferments
change the sugar into dextrose and glucose sugars; then the alcoholic
ferment produces alcohol and carbon dioxid from the invert sugars, and
finally the acetic acid ferment completes the work by converting the
alcohol into acetic acid. The chemical changes