EFFECTS OF BAD YEAST. 189 



used, but there is no need for the bread to be bad in 

 consequence; because it is quite possible to remove 

 the sour taste of the yeast before using it. The ad- 

 dition of a small quantity of carbonate of lime, soda, 

 or magnesia, will effect this ; but, of course, care must 

 be taken not to use more of either of these salts than 

 is necessary to neutralize the acid matter present. 



462. The sour taste which bread acquires when it 

 is badly made, or when damaged flour is used, is less 

 easily corrected. Nevertheless, it may be greatly 

 diminished, if not altogether prevented, by the ad- 

 dition of a small quantity of carbonate of soda or 

 ammonia. The latter salt may often be employed 

 with great advantage, and, being a volatile salt, it is 

 raised in vapor by the heat of the oven. Any excess 

 of it, therefore, is driven off by the heat, and in es- 

 caping, assists in making the bread lighter. 



463. Yeast is not unfrequently bitter, and then 

 communicates a very unpleasant flavor to the bread 

 made with it. This may be derived from hops, espe- 

 cially when the yeast is collected from beer which is 

 strongly hopped. But yeast sometimes also acquires 

 a bitter taste from keeping, which is quite independ- 

 ent of that derived from the hops ; this also may be 

 remedied to some extent in various ways. One way, 

 which is said to be very effectual, consists in throwing 

 into the yeast a few clean cinders freshly taken from 

 the fire, but allowed to cool a little on the surface. 

 When cold, the cinders fall to the bottom, and the 

 yeast is poured off. This operation appears to de- 



