256 



DAIRY TECHNOLOGY 



By concentrating the milk by evaporation of water the 

 per cent of acid and other non-volatile chemicals are in- 

 creased. This may be illustrated as follows: Supposing 

 the milk to be condensed contained 0.2 per cent acid, and 

 this milk was condensed to one half its volume, the per 

 cent acid contained in the finished product would be twice 

 its original per cent, or 0.4 per cent. By further conden- 

 sation, the per cent acid will increase proportionately. 

 The great importance of having milk with a low acid con- 

 tent for condensed milk is readily understood. This in- 

 creased per cent of acidity after condensation and increased 

 heat during the condensation period are likely to cause 

 the milk to curdle and become lumpy. This latter is 

 very undesirable. Condensed milk should have a uni- 

 formly smooth body. If it has not, the trade rejects it. 

 It is possible that other components of milk affect the 

 properties of the finished product similarly to the acid on 

 concentration and heating. 



The following table 1 shows the results of evaporating 

 fresh milk to different degrees of concentration. 



The different lots of evaporated milk were made from 

 the same batch of fresh milk. 



Another kind of undesirable condensed milk is that 

 which is churned. It is important that the butter fat be 

 properly emulsified with the remainder of the milk com- 



1 Indiana Bui. 143. 



