74 



of the milk has begun but not until the cream has reached 

 a temperature of 70 F. The cream thus coming in con- 

 tact with the starter as it leaves the separator insures a 

 vigorous development of the starter germs, so that by the 

 time the separation is completed, the starter fermentation 

 is almost certain to predominate, especially when a large 

 amount of starter is used. 



2. The maximum amount of starter that may be con- 

 sistently used is one pound to two pounds of cream. A 

 larger amount than this would be liable to result in too 

 thin a cream. Experience teaches us that the maxi- 

 mum richness of cream permissible in clean skimming 

 under average conditions is 50%. Adding one pound of 

 starter to two pounds of such cream would give us 

 a 33 T ~3 % cream, the ideal richness for churning. But 

 this amount of starter is rarely permissible on account 

 of the poor facilities for controlling the temperature of 

 the cream. 



3. Since the lactic acid bacteria develop best at a 

 temperature of 90 to 98 F. it would seem desirable to 

 ripen cream at these temperatures. But this is not 

 practicable because of the unfavorable effect of high tem- 

 peratures on the body of the cream and the butter. Good 

 butter can be produced, however, under a wide range of 

 ripening temperatures. The limits may be placed at 60 

 and 80. Temperatures below 60 are too unfavorable 

 for the development of the lactic acid bacteria. Any 

 check upon the growth of these germs increases the 

 chances for the development of other kinds of bacteria. 

 l>ut it may be added that when cream has reached an 

 acidity of .4% or more, the ripening may be finished at a 

 temperature between 55 and 60 with good results. In 

 general practice a temperature between 60 and 70 gives 



