190 THE ARTS AND INDUSTRIES 



This explains why sour milk can be used with soda for 

 pancakes or griddle cakes. Should the baking soda be 

 added to the milk or should it be dissolved in a little water 

 and added to the mixture after the sour milk has been 

 stirred in? Explain. 



When bread is made yeast is added to make it "rise." 

 The yeast uses the sugar which is added to the mixture, 

 and some of the flour is changed to a kind of sugar which 

 the yeasts can use. Carbon dioxide is produced which 

 forms the bubbles and thus the dough swells and becomes 

 porous and tender. Most of the alcohol bakes out. Why 

 is bread made with warm water during the cold weather? 

 Another use for yeast is in the making of homemade 

 root beer. The stopples "pop" when the bottles are 

 opened on account of the large amount of carbon dioxide 

 which the liquid contains. 



79. Alcohol for Industrial Purposes. 



Alcohol may be made from any vegetables or stalks 

 of crops, which contain starch or sugar, by means of 

 yeast. This means that much of the waste in crops due 

 to small vegetables or some damage which renders the 

 vegetables unfit for sale may be turned into alcohol 

 which is very valuable for many of the arts and indus- 

 tries. Alcohol is used in large quantities as a solvent, 

 and it is also used for lighting, heating, cooking, and 

 for running engines. 



The United States Government has removed the tax 

 on alcohol if it is not to be used as a drug or drink. The 

 only requirement is that something must be added to the 

 alcohol which will render it unfit for persons. Alcohol 

 in this condition is called denatured. 



