BAKING POWDER: a compound used in place of yeast, in which an acid acting upon an alkali generates carbon-dioxide (carbonic acid gas). As this action takes place as soon as the powder is moistened, the dough is made ready for baking more promptly than when yeast is used.
Practically all baking powders are composed of an acid, an alkali and a filler. The all is nearly always Bicarbonate of Sodium, and starch is generally employed as the filler, but there is a wide variation in the acid constituent used, and baking powders may be conveniently classed according to its nature. They may be recog nized as follows : (1) Tartrate Powders, in which the acid constituent is cream of tartar or tartaric acid :—Royal, Dr. Price's, Cleveland's, Sea Foam, etc.
(2) Alton, Powders, in which the acid constituent is generally a calcined double sulphate of aluminum and sodium :—Davis, Calumet, K. C., etc.
(3) Phosphate Powders, in which the acid constituent is acid calcium phos phate :—Horsford's, Wheat, etc.
In the process of baking, the chemical constituents undergo certain changes, so that the residue in the finished bread is of somewhat different character from the original ingredients. That left in food, when cream of tartar powders are used, is rochelle salts ; powders founded on phosphates leave calcium and sodium phosphates, and alum powders leave glauber's salt and a salt of aluminum. The quantity is,
however, in each case very small, The date when baking powder was first manufactured is involved in some doubt, but it is known that Preston & Merrill, of Boston, made it prior to 1855, the common name ,then being "yeast powder." Phosphate powders were invented by Professor E. N. of Cambridge, Mass., in 1857, and their manufacture commenced soon thereafter by the Rumford Chemical Works, of Providence, R. I. Royal Baking Powder was first introduced in 1867 and Alum powders about the year 1875.
Grocers should not sell baking powders which do not give entire satisfaction, even if they are cheap and pay a good profit, because the loss resulting from a dissatisfied customer is likely to be much more than the profit on the baking powder. Private brands should be avoided because of the uncertainty as to their true character and legality under the Pure Food Laws. It is safest to buy only well known "regular" brands bearing the name of a responsible manufacturer.
Care should be taken to keep all baking powders in a dry place as they lose their strength if exposed to dampness.