242 MANUAL OF MILK PRODUCTS 



and its flavors are usually bad. About one-third to one pint of 

 milk is sufficient for most cultures. Glass jars, enameled ware, 

 china, earthenware, and tin are the best utensils for this pur- 

 pose. 



"The lactic acid bacteria grow the most rapidly at 95 to 108 

 F. But in impure cultures, like a starter or milk, there are 



FIG. 48. Power starter can with water jacket and mechanical stirrer. 



bacteria that can compete more successfully with the lactic acid 

 fermentation at high or low temperatures than at mean temper- 

 atures. Thus at high temperatures stale flavors and gassy fer- 

 mentations are frequent, and it is difficult to avoid over-ripening. 

 Bitter and other undesirable flavors are common at low temper- 

 atures. It is possible to ripen successfully at 55 to 90, but the 

 best flavor is developed at 60 to 75 F. It is better to ripen a 



