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cream of tartar / baking powder

CREAM OF TARTAR. An acid concrete salt, deposited from wines completely fermented, and adhering to the sides of the casks in the form of a hard crust. It is white or red, the white being the most esteemed. When pure, it is called cream of tartar, and when crude, argal or argol. — Webster, 1882

Cream of tartar is the common name for potassium hydrogen tartrate, an acid salt used in cooking. It exists naturally in grape juice, but being insoluble in alcohol, it is gradually deposited, in the form of argol, as the sugar of the juice becomes converted into alcohol by fermentation. In the preparation of cream of tartar, the argol is dissolved in hot water, to which charcoal or fine clay is added, to take up the coloring matter; by boiling and filtering, a clear colorless solution is obtained. When cooled, the cream of tartar separates as crystals. These crystals, after being exposed to the air for several days, become whiter and constitute the crystals of tartar, or, when ground to powder, cream of tartar. Although cream of tartar is, practically speaking, tartaric acid, it usually contains from 5 to 10 percent of tartrate of lime, while other impurities may also be present. Cream of tartar is readily soluble in hot water, though it takes 60 parts of cold water to dissolve one part of it. Cream of tartar has an acid taste and a gritty feel. — William and Robert Chambers, Chambers’s Encyclopedia: A Dictionary of Useful Knowledge, Volume III (Philadelphia: J.B. Lippincott & Co., 1889), 551. Photo shows vats of cream of tartar in California wine country, early 1900s.

BAKING POWDER. A leavening made of two parts cream of tartar to one part baking soda, normally “filled out” with cornstarch. — Webster, 1882

Baking powder consists of baking soda (saleratus) and one or more acid salts (cream of tartar), plus cornstarch to absorb any moisture so that a reaction doesn’t take place until a liquid is added to the batter. In The Long Winter, Caroline Ingalls mixes cream of tartar and saleratus to make her own baking powder in order to produce a “sugar-frosted loaf of cake.”

Without eggs, butter, or milk, it is unclear exactly what kind of cake Mrs. Ingalls might have made; it must have been more like a large, sweet, raised biscuit than a traditional cake.

According to the July 1885 American Druggist, a monthly journal published by William Wood & Co., New York, the best baking powder consisted of 7 parts cream of tartar and 3 parts sodium bicarbonate, with 2 parts starch or flour added if the baking powder was to be kept any length of time. The ingredients were thoroughly mixed by sifting together. Commercial preparations of baking powder became available in the 19th century.


cream of tartar (FB 12, 28), see also saleratus