DIFFERENT KINDS OF YEAST 



99 



Fig. 39. Yeast from 

 a dried yeast cake. 



commercial product. For the ordinary housekeeper the 

 bother of making the yeast brew is so great, the results so 

 unreliable, and the expense of compressed yeast so slight, 

 that the latter is now almost universally 

 used. To-day many bakers have given 

 up making their own yeast brews and 

 depend upon compressed yeast. 



Dried Yeast. A second type of com- 

 mercial yeast is the dried yeast cake. 

 This is prepared by cultivating yeast, 

 mixing the product with certain ingredients, chiefly starch, 

 pressing into cakes, and then drying the product at a lov/ 

 heat. The drying perhaps injures or kills some of the 

 yeast plants, but a great many of them remain uninjured, 

 and may be found for a long time in the dried yeast cake, 

 still alive and capable of growing if placed under proper 

 conditions (Fig. 39). In order that they may begin to 



grow again they must be mois- 

 tened, and in using a dried yeast 

 cake it is best to soak it in 

 warm water to which has been 

 added a small amount of sugar. 

 The sugar furnishes food for 

 the yeast plants, and by soak- 

 ing them in warm water they 

 are soon brought to a con- 

 dition of growth, so that when 

 added to the bread dough they readily enough produce a 

 fermentation (Fig. 40). 



The dried yeast cakes are not quite so convenient to 

 use as the compressed, but a little experience will enable 



Fig. 40. The same yeast after a 

 few hours' growth. 



