Foods, their selection and preparation

Sirups contain varying amounts of acid which may be used to release carbon dioxide from the soda in mixtures such as ginger- bread, brown bread, dark cakes, and cookies normally containing molasses or other sirup. The percentage of acid in true molasses is higher than that in sour milk, but the acid content in molasses is more variable. It is well to know the acid value of the molasses before using it in combination with soda in flour mixtures. One-half to one teaspoon of soda is used to each cup of molasses. The variations from this amount with the dif- ferent kinds of sirup are shown in table below. Table LX • Amount of Soda to Neutralize Acid in One Cup of Sirup Sirup Amount of Soda Corn sirup .... Teaspoon ¥ Honey . ¥ to \ Molasses . \ to 1 Sorghum . i to 1 In substituting another form of sirup for molasses, it is necessary to make the cor¬ rection indicated in the amount of soda called for, and to add baking powder to complete the leavening; or to add the amount of soda called for, and make up the acid deficiency by the addition of some other form of acid. Sorghum often is less acid than molasses, but it may be just as acid. Honey usually contains a sufficient amount of acid to make it of value in the liberation of carbon dioxide from soda. Just as with other sirups, the acidity varies with honey from different sources. Corn sirup is usually lower in acid than the other sirups and, therefore, soda usually [291] is omitted when it is used. In recipes calling for both molasses or other sirup and sour milk, the acid content of the two should be considered in determining the amount of soda necessary. Cream of tartar is an acid powder that formerly was used in the household with soda as a means of leavening. At present it is little used for this purpose except in commercial baking powder, where it has been carefully weighed and mixed. Baking Powders. Commercial baking powder was unknown a hundred years ago. Today it is consumed in the United States at the rate of more than a pound per person each year. All baking powders are combina¬ tions of an acid powder and baking soda in such proportion that they combine to form a salt. The carbon dioxide contained in the soda is given off in the batter or dough. In commercial baking powder, an inert filler or stabilizer is added which serves a double pur¬ pose: (1) to keep the two active ingredients separated mechanically and to absorb any moisture, thus preventing the reaction of the powder in the can; (2) to serve as a filler. All baking powders are made up to yield a standard amount of carbon dioxide; so the weight of the soda is constant (approximately 25 per cent). The weight of the different forms of acid required to release the carbon dioxide varies. In standardizing the powders, these differences in weight are made good by the amounts of inert filler added. In most baking powders the stabilizer is cornstarch, but in certain types of powder, calcium car¬ bonate is used in addition to cornstarch. It is probable that such a baking powder which supplies calcium to the food baked with it may be of value nutritionally. Two teaspoons of baking powder contain approximately \ teaspoon of baking soda. It is required by law that all commercial bak¬ ing powders contain the essential constitu¬ ents in such proportion that the powders