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the temperature at which churning should be begun 

 in sweet cream is 12'5 C. (54*5 Fahr.), and for 

 sour cream 16 C. (60*8 Fahr.). Sweet cream 

 seems to require to be churned for a longer time 

 than sour cream, and the loss of fat is very much 

 greater in the former case than in the latter, 

 indeed, the loss has been calculated by certain 

 American experts to amount to nearly 50 per cent 

 more. The length of time during which churning 

 should last may be said to vary from thirty to forty- 

 five minutes. The effect of diluting cream with 

 water before churning is to increase the period of 

 time required. The loss of fat which, under such 

 circumstances, takes place is slightly greater, and the 

 resulting butter is not so firm. 



The Bacteria of Butter. We now come to 

 consider a very important aspect of butter-making, 

 viz. the relation of bacterial life to butter. It is 

 beyond doubt that the flavour, aroma, and the many 

 qualities which good butter possesses, are due to the 

 action of bacteria. We have already pointed out 

 that, after separating the cream from the milk, it is 

 soured, or "ripened," for a number of hours before 

 being churned. This is effected by allowing it to 

 stand in a warm place for some time, and sometimes 

 by adding some sour cream. Now one reason for 

 this is that the milk globules, under such circum- 

 stances, coalesce more easily than they do in sweet 





