CHAPTER VI 



YEASTS IN THE HOUSEHOLD 



As Enemies. Yeast must, in general, be looked upon as 

 the housewife's friend, since in almost all its relations to 

 household affairs it produces only desirable results. In a 

 few instances we find yeast producing trouble. Its occa- 

 sional presence in jellies and preserves has already been 

 noticed, as well as in the fermentation of maple sugar. 

 Any sirup containing fruit sugar, cane sugar, or beet 

 sugar may undergo spontaneous fermentation in our 

 homes. In dairy products yeasts occasionally produce 

 mischief, since the bitter tastes of milk and cheese are 

 sometimes caused by their growth. This will rarely if 

 ever trouble the housewife, although it may cause mis- 

 chief for the dairymen. It is only in the fermentation of 

 sugary substances, like jellies and sirups, that the house- 

 wife is troubled with undesired fermentation. One prac- 

 tical suggestion in this connection may be of use. Since 

 boiling will kill yeasts, any material which shows the easily 

 recognized sign of fermentation — the peculiar, sharp, 

 pungent taste — can be preserved from further injury if 

 it is merely heated to the temperature of boiling. No 

 further fermentation will then occur, provided the subse- 

 quent entrance of yeast is prevented by protecting the 

 material from the air. If the material cannot be heated, 

 there is no satisfactory remedy for a fermentation once 

 started. 



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