BAKING POWDERS 2 2Q 



water alone are kneaded and baked in loaves, the result is a 

 mass so compact and hard that human teeth are almost 

 powerless to crush and chew it. The problem is to separate 

 the mass of dough or, in other words, to cause it to rise and 

 lighten. This can be done by mixing a little soda in the 

 flour, because the heat of the oven causes the soda to give off 

 bubbles of gas, and these in expanding make the heavy mass 

 slightly porous. Bread is never lightened with soda because 

 the amount of gas thus given off is too small to convert 

 heavy compact bread dough into a spongy mass ; but biscuit 

 and cake, being by nature less compact and heavy, are suf- 

 ficiently lightened by the gas given off from soda. 



Buj: there is one great objection to the use of soda alone 

 as a leavening agent. After baking soda has lost its carbon 

 dioxide gas, it is no longer baking soda, but is transformed 

 into its relative, washing soda, which has a disagreeable taste 

 and is by no means desirable for the stomach. 



Man's knowledge of chemicals and their effect on each 

 other has enabled him to overcome this difficulty and, at the 

 same time, to retain the leavening effect of the baking soda. 



211. Baking Powders. If some cooking soda is put into 

 lemon juice or vinegar, or any acid, bubbles of gas immedi- 

 ately form and escape from the liquid. After the efferves- 

 cence has ceased, a taste of the liquid will show you that the 

 lemon juice has lost its acid nature, and has acquired in 

 exchange a salty taste. Baking soda, when treated with an 

 acid, is transformed into carbon dioxide and a salt. The various 

 baking powders on the market to-day consist of baking soda 

 and some acid substance, which acts upon the soda, forces it 

 to give up its gas, and at the same time unites with the resi- 

 due to form a harmless salt. 



Cream of tartar contains sufficient acid to act on baking 

 soda, and is a convenient and safe ingredient for baking pow- 



