CASEIN 225 



The buttermilk, when drawn from the churn, is pumped 

 into large vats or tanks, steam is turned directly into the 

 buttermilk, and the temperature is brought to about 160 F. 

 The hot buttermilk is left undisturbed for several hours, 

 or over night. It is then run over a cooler into a smaller 

 vat, for convenience in handling, and the temperature 

 brought to about 100 F. Sulphuric acid is added in the 

 proportion of about six quarts of acid to 300 gallons of 

 buttermilk. The proportion is varied with the season of 

 the year, the acidity and the condition of the buttermilk. 

 An excess of acid will produce a dark-colored casein that 

 has a low market value. Insufficient acid causes incom- 

 plete gathering of the curd; hence, many small particles 

 are lost in the whey. Within one hour from the time the 

 acid is added the whey may be readily drawn off and the 

 curd put to press. The pressing, grinding and drying of 

 the curd is carried on in a manner similar to that of han- 

 dling curd from skim milk. 



Casein from buttermilk differs from casein from skim 

 milk in the following particulars: 



Buttermilk casein is darker in color, contains a higher 

 percentage of fat, is less soluble, and cannot be used so 

 extensively nor for such high-grade products as can skim- 

 milk casein. The former has a market value from ten to 

 sixty per cent .lower than that of the best-grade skim milk 

 casein. 



Casein Glue. The crude casein may be converted into 

 a glue by the following simple process: To the casein add 

 one-fourth of its weight of distilled water and one to four 

 per cent of bicarbonate of soda. Mix thoroughly, then add 

 a quantity of distilled water equal to the original amount 

 used, to complete the solution, and let it stand from five 

 to six hours. At the end of this time the glue will be 



