154 YEAST AND BREAD MAKING 



The bread of antiquity. The original method of bread 

 making and the method employed by savage tribes of to-day 

 is to mix crushed grain and water until a paste is formed, and 

 then to bake this over a camp fire. The result is a hard compact 

 substance known as unleavened bread. A considerable im- 

 provement over this tasteless mass is self-raised bread. If 

 dough is left standing in a warm place a number of hours, it 

 swells up with gas and becomes porous, and when baked, is 

 less compact and hard than unleavened bread. Exposure to 

 air and warmth brings about changes in dough as well as in fruit 

 juices, and alters the character of the dough and the bread 

 made from it. Bread made in this way would not seem palat- 

 able to civilized man of the present day, accustomed, as he is, 

 to delicious bread made light and porous by yeast ; but to the 

 ancients, the least softening and lightening was welcome, and 

 self-fermented bread, therefore, supplanted the original un- 

 leavened bread. 



Soon it was discovered that a pinch of this fermented dough 

 acted as a starter on a fresh batch of dough. Hence, a little 

 of the fermented dough was carefully saved from a batch, 

 and when the next bread was made, the fermented dough, or 

 leaven, was worked into the fresh dough and served to raise 

 the mass more quickly and effectively than mere exposure to 

 air and warmth could do in the same length of time. This 

 use of leaven for raising bread has been practiced for ages. 



Grape juice mixed with millet ferments quickly and strongly, 

 and the Romans learned to use this mixture for bread raising, 

 kneading a very small amount of it through the dough. 



The cause of fermentation. Although alcoholic fermenta- 

 tion, and the fermentation which goes on in rising dough, were 

 known and utilized for many years, the cause of the phenome- 

 non was a sealed book until the nineteenth century. About 

 that time it was discovered, through the use of the microscope, 



