THE ANALYSIS OF BUTTER 81 



be useful as confirmatory, and a reaction for sesame 

 oil will establish the presence of margarine, while 

 vegetable oils give the phytosteryl acetate test. 

 The average figures for butter and margarine are : 



TABLE IX 



Cocoa-nut oil has a different composition from that 

 of margarine ; but as it lowers the Reichert-Wollny 

 figure, while at the same time raising the Polenske 

 figure and potash absorption, and lowering the insoluble 

 fatty acids, iodine absorption and the refractometer 

 figure, its detection is not difficult. Positive evidence 

 of its presence can be obtained by Hinks' method. 



Application of Analysis to Buttermaking. 

 The acidity of the cream should be taken to see if it 

 is properly ripened ; an acidity of 60 to 70 is usually 

 suitable. 



The fat in the butter-milk is an important item, as 

 this represents loss ; 0.2 per cent, shows satisfactory 

 churning, while more than i per cent, even with very 

 thick cream indicates bad working ; either the ripening 

 has not been properly done, the churning is too rapid, 

 or the temperatures are wrong. 



The amount of butter yielded by milk may be cal- 

 culated by subtracting o.i from the percentage of fat, 

 multiplying by 7, and dividing by 60 ; this gives the 

 number of pounds of butter per gallon of milk. 



The following Table will give the amount of butter 



F 



