FoodNet

Foods, their selection and preparation

1935

Page 266

Presented as published in 1935. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
yield not less than 12 per cent available car¬ bon dioxide gas. While the various brands of baking powders may differ in strength, few, if any, are manufactured to yield less than 13 per cent or more than 18 per cent by weight of available carbon dioxide.1 Most powders yield about 14 per cent carbon di¬ oxide when fresh. This means that 100 grams of baking powder will release approximately 14 grams of carbon dioxide. The price of baking powder is no measure of its leavening ability, but is based on the cost of the acid ingredient. Kinds. The variable ingredient in differ¬ ent baking powders is the acid. There are three general kinds of powders, depending upon the kind of acid they contain. Each powder is named according to its acid¬ reacting component. These are: 1. Tartrate Powders, or those in which the acid is in the form of cream of tartar, or cream of tartar plus tartaric acid. There are at least two well-known brands of this kind of powder. These are quick-acting baking powders. 2. Phosphate Powders, or those in which the acid component is an. acid phosphate of calcium. There are two modifications of this kind of powder. Two old well-known brands belong to one modification, which contains the hydrate of monocalcium phosphate and is comparatively fast-acting. The other modification is fairly new. The acid is in a less-soluble form of the monocalcium phos¬ phate and so liberates gas more slowly than the original phosphate powders. 3. Sodium Aluminum Sulphate Pow¬ ders, often called S.A.S. baking powders, or those containing two acid components — hydrate of monocalcium phosphate (the same as the phosphate powders) and sodium alu- ^Available carbon dioxide is the amount of carbon dioxide liberated from the baking powder under mixing and baking conditions, and is that part which accomplishes the actual leavening. minum sulphate. The latter ingredient is not an acid, but it forms an acid by the addition of water. This hydrolytic process is slow and incomplete in the batter or dough until the mixture is heated. These powders, there¬ fore, are double-acting and are designated in that way, one reaction taking place in the cold, the other during cooking. This type of baking powder is widely distributed. As has been indicated, these three kinds of baking powders behave differently in flour mixtures, giving off carbon dioxide at different rates. For this reason they should be used in different proportions and also handled differently. With tartrate powders, which are rapid in reaction, much of the gas may be formed during mixing. As much as 90 per cent of the gas may be liberated at room temperature. This means one must work rapidly when using this kind of powder. On the other hand, the S.A.S. powders are slowest in reaction and must be heated before the reaction is complete. When these powders are used there is no special need for haste; in fact, the batter or dough may be made up beforehand and held until time for baking. Table LXI compares the three kinds of baking powders as to acid components, rate of reaction, and average amounts to use to each cup of flour. Good results can be ob¬ tained with all kinds of baking powders if each is properly handled.