CONDENSED AND POWDERED MILK 



463 



Increase of the Per Cent of Acid as the Concentration of the 

 Evaporated Milk Increases and Its Effect on the Cur- 

 dling of the Casein 



Lot No. 



Concentration 



Per Cent Acid 



Condition op Casein 



1 



1.58 : 1 



.30 



Not precipitated 



2 



1.74: 1 



.34 



Not precipitated 



3 



1.9 :1 



.40 



Not precipitated 



4 



1.99:1 



.43 



Not precipitated 



5 



2.11 : 1 



.48 



Small lumps of curd 



6 



2.25 : 1 



.54 



Large lumps of curd 



The different lots of evaporated milk were made from the 

 same batch of fresh milk. The fresh milk tested .17 per cent 

 lactic acid. Evaporated milk with a concentration of 1.58 

 parts of fresh milk to 1 part of evaporated milk contained .30 

 per cent acid. There was a continuous rise in the per cent of 

 acid, the more concentrated the product. Evaporated milk 

 condensed at the ratio of 2.25 : 1 contained .54 per cent acid. 



The degree of concentration is also an important factor in 

 determining the marketable properties of the finished product. 

 This is shown by the results of work done by Hunziker, 1 who 

 conducted experiments at different times during the season. 

 The results of these experiments are given in three tables which 



follow : 



June Experiment 



No. 



Concentration 



Milk Solids 



Condition of Sample One Month after 

 Manufacture 







per cent 





1 



1.61 : 1 



20.40 



Fat separated and churned, 

 no curd 



2 



1.96:1 



24.87 



Smooth, no separation, no curd 



3 



2.00 : 1 



25.38 



Smooth, no separation, no curd 



4 " 



2.20 : 1 



28.02 



Curdy, lumps of curd, fat 

 not separated 



5 



2.52:1 



31.99 



Curdy, lumps of curd, fat not 

 separated 



Total solids in fresh milk, 12.68 per cent. 

 Acidity in fresh milk, .16 per cent. 



1 Indiana Bui. 143. 



