CHEMISTRY OF BAKING 29 



The result was a hard, compact mass called unleavened 

 bread, which was very hard to masticate, and the taste 

 was not that of modern bread. If the paste made of 

 water and crushed grain was allowed to stand for a few 

 hours, the wild yeast of the air would fall into it and start 

 to grow and produce carbon dioxide gas. This made 

 a more porous loaf than the unleavened bread and was a 

 great improvement over it. It was called self -raised bread. 



This was discovered perhaps by some good housewife 

 who, after making her batter, had to attend to some other 

 duties for a few hours and on returning found that her 

 dough had increased in size. This she baked and found 

 that it had a better quality than any she had ever tasted, 

 so after this she let all of her dough stand a few hours 

 before baking, and of course told her neighbors about 

 her new bread. 



Soon it was also learned that if a bit of this self- 

 raised dough was saved and put into the next baking, 

 the batter would rise much faster and be much more 

 porous and eatable than the self-raised bread. This 

 was another great improvement and was widely used for 

 many centuries. It is used somewhat even today. A 

 very similar method was used by the Romans. They 

 learned that grape juice mixed with millet would grow 

 yeast plants rapidly, so they used this mixture for bread 

 raising by kneading a small quantity of it into the dough, 

 then allowing the dough to stand a while before baking. 



Through all these centuries the results of fermentation 

 were known and used, but it was not known that the 

 yeast plant was the cause, nor until the nineteenth cen- 

 tury did anyone know that there was such an organism 

 as the yeast plant. The microscope was necessary to 

 discover the little plant in fermenting liquids, to learn 



