Bacteria and Butter Making. 141 



It is not necessary that the cream be ripened, in order 

 to have the fat acquire a flavor, for if sweet cream is 

 churned with a considerable proportion of sour milk, the 

 butter will have much the same flavor, both as to intens- 

 ity and kind, as though the cream had been allowed to 

 sour naturally. A process of butter making known as 

 the LeClair method is based on this principle. The 

 flavor-producing substances can also be absorbed by the 

 butter after it is churned, by working the butter in con- 

 tact with sour milk. Attempts have been made to add 

 pure lactic acid to the cream, instead of allowing the 

 acid to be formed by the bacteria, but while the physical 

 effect on the cream is the same, the flavor and aroma of 

 the butter are deficient, because the acid itself does not 

 supply the necessary aromatic products. This emphas- 

 izes the importance of the by-products of the acid fer- 

 mentation other than the lactic-acid. 



In the past numerous attempts have been made to find 

 organisms that might be added to the cream, in order to 

 produce the delicate flavor characteristic of the best 

 type of butter. Some bacteriologists have claimed that 

 the source of the flavor-giving substance was to be found 

 in the decomposition products of the nitrogenous con- 

 stituents of the milk. None of these attempts have stood 

 the test of practical use in creameries, and it has been 

 demonstrated that the finest type of butter can be made 

 by the use of lactic bacteria alone. Formerly, when but- 

 ter was made wholly from cream soured under natural 

 conditions, a much higher degree of flavor was devel- 

 oped. Under present market demands, a less pro- 

 nounced flavor is desired, a condition more readily met 

 by the use of modern methods. 



