234 GENERAL SCIENCE 



salt, but bread made by this process has not been very satisfactory 

 because of its flavor. 



Baking Soda and Molasses. Molasses contains some free acid 

 which acts upon baking soda and produces carbon dioxide. Vinegar 

 is sometimes added when the acid in the molasses is not sufficient. 

 Gingerbread is made by this process. 



Sour Milk Bread. Sour milk contains an acid known as lactic 

 acid. When sour milk and baking soda are used to produce carbon 

 dioxide for raising bread, sodium lactate, a harmless salt, is left in 

 the bread. An excess of baking soda causes the bread to become 

 yellow and unwholesome, since washing soda is formed in the 

 product. 



Baking Soda and Cream of Tartar. Cream of tartar (tartaric 

 acid) is obtained from Argol, a product found on the inside of wine 

 barrels. The tartaric acid has crystallized from the grape wine. 

 When cream of tartar and soda are used for making bread, carbon 

 dioxide is formed, and Rochelle salts is left in the bread. A great 

 deal has been said about the unwholesomeness of this residue, but, 

 although a loaf of bread will have more of this salt than a seidlitz 

 powder, the amount of bread eaten at one meal is so small that the 

 effect on the system may be disregarded. Rochelle salts has a 

 slightly laxative effect. A good baking powder may be made by 

 mixing two pounds of baking soda with four pounds of cream of 

 tartar and a little less than two pounds of starch. The starch 

 and soda should be mixed first. 



Phosphate Baking Powder. Another type of baking powder is 

 made from calcium acid phosphate and baking soda. This baking 

 powder leaves calcium phosphate and sodium phosphate in the bread. 



Burnt Alum Baking Powder. A great many objections have been 

 made to the use of alum baking powder because this powder leaves 

 in the bread aluminum hydroxide, which is not soluble in the gas- 

 tric juices of the stomach. Alum has an astringent action on the 

 system, producing a tendency to constipation. As ammonium alum 

 has an irritating effect on animal tissue it is considered very 

 objectionable. 



Burnt alum baking powder leaves in the bread aluminum hy- 

 droxide, sodium sulphate (Glauber's salt), and potassium sulphate. 



