BUTTER-MAKING 243 



or sour-cream butter. The process is really a fermentation, the 

 ripening bacteria acting on each and all of the constituents of the 

 milk, resulting in the production of various bye-products. This 

 fermentation is a decomposition, and just as we found when dis- 

 cussing fermentation, so here also the action is only beneficial if 

 it is stopped at the right moment. If, for example, instead of being 

 stopped on the second day, it is allowed to continue for a week, the 

 cream will degenerate and become offensive, and the pleasant ripen- 

 ing aroma will be changed to the contrary. Speaking generally, 

 about 25 per cent, of cream bacteria exert a favourable effect on 

 butter, and 10-15 per cent, a deleterious effect. Many of the former 

 are acid-producers, and are widely distributed. 



Bacteriologists have demonstrated that butters possessing 

 different flavours have been ripened by different species of bacteria. 

 Occasionally, one comes across a dairy which seems to be impregnated 

 with bacteria that improve cream and flavour well. In other cases 

 the contrary happens, and a dairy becomes impregnated with a 

 species having deleterious effects upon its butter. Such a species 

 may be favoured by unclean utensils and dairying, by disease of the 

 cow, or by a change in the cow's diet. Thus it comes about that the 

 butter-maker is not always able to depend upon good ripening for 

 his cream. At other times he gets ripening to occur, but the .flavour 

 is an unpleasant one, and the results correspond. It may be bitter or 

 tainted, and just as certainly as these flavours develop in the cream, 

 so is it certain that the butter will suffer. Fortunately, the bacterial 

 content of the cream is generally either favourable or indifferent in 

 its action. Thus it comes about that the custom is to allow the 

 cream simply to ripen, so to speak, of its own accord, in a vat 

 exposed to the influence of any bacteria which may happen to be 

 around. This generally proves satisfactory, but it has the great 

 disadvantage of being indefinite and uncertain. Occasionally it 

 turns out wholly unsatisfactory, and results in financial loss. Shortly, 

 it may be said that cream-ripening assists the making of butter in 

 four ways : — 



1. Churning is easier and more effectual. 



2. The yield of butter is increased. 



3. The butter has better keeping qualities. 



4. The flavour and aroma are more satisfactory. 



Control of Ripening Process. — There are various means at our 

 comniand for improving the ripening process. Perfect cleanliness 

 in the entire manipulation necessary in milking and dairying, com- 

 bined with freedom from disease in the milch cows, will carry us a 

 long way on the road towards a good cream-ripening. Eecently, 

 however, a new method has been introduced, largely through the 



