2l6 SCIENCE AND PRACTICE OF CHEESE-MAKING 



fat in cheese-making, the result found by multi- 

 plying milk- fat by i.i is too high. (2) The estimate 

 of 5.9 pounds as the measure of the cheese-making 

 value of casein in skim-milk is based upon skim- 

 milk of average composition. Therefore, in milk 

 low in percentage of casein, 5.9 is too high, while 

 in milk high in casein, the figure is too low. The 

 method is faulty in that its accuracy depends upon 

 a uniform percentage of casein in all milks, and we 

 know that there are quite wide variations. 



METHOD BASED ON FAT AND CASEIN IN 

 MILK (3) 



This method of finding the yield of cheese, stated 

 in the form of a rule, is as follows: Multiply the 

 number representing the per cent of fat in milk 

 by i.i, and to this add the result obtained in multi- 

 plying by 2.5 the number representing the per cent 

 of casein in milk. This formula was originally 

 worked out at the Wisconsin experiment station and 

 was first extensively applied and confirmed by the 

 work of the New York experiment station. 



This method is based upon the following facts: 

 ( i ) Milk- fat is capable of holding mechanically 

 one-tenth of its own weight of water. This has 

 been already explained in detail in connection with 

 the discussion of method 2. (2) The reason for mul- 

 tiplying the amount of casein in milk by 2.5 is 

 found in the yield of cheese from skim-milk and 

 also in the results of some experimentar work done 

 at the New York experiment station. A prepara- 

 tion of pure casein was made, dried, and then al- 

 lowed to absorb as much water as it would be 



