202 CANADIAN DAIRYING. 



" 4. A good natural skim-milk starter is practically a pure 

 culture of acid-producing bacteria. 



" 5- The most common souring organism (Bacterium lactici) 

 gives the best results. 



" 6. The most important factors in cream ripening are the 

 development of typical acid fermentations and the suppression 

 of injurious types." 



CHURNING. 



Churning changes the liquid fat to a solid, in 'addi- 

 tion to massing the fat globules. This is done by 

 means of a churn, which should be easy to clean, easy 

 to get the cream into it, and easy for getting the butter 

 out ; and it should give sufficient concussion to the 

 cream to bring the butter in less than one hour. It is 

 necessary to cool the cream to churning temperature 

 from two to four hours before churning, in order to 

 get a proper body and texture in the butter. If color- 

 ing is used, it should be put into the cream when 

 in the vat, or directly after it has been placed in the 

 churn. The basis for coloring may be at a certain 

 rate per thousand pounds of milk (usually about 

 one dram), according to the fat content of the 

 cream, or at so much per pound of butter fat. No 

 coloring is necessary in the summer time, and it is 

 always safer to under-color rather than over-color 

 butter. The amount of color required must be deter- 

 mined by each buttermaker, as it varies according to 

 the natural color of the milk, the demands of the 

 market, the strength of the coloring, whether the cream 

 has been pasteurized or not, and upon the amount of 

 salt which is added. Butter colors are of two general 



