66 A Handbook for Dairymen 



These racks are placed in a dry kiln and the casein 

 dried for twenty-four hours. The heat for drying 

 is obtained by blowing air over hot radiators. ^ 

 temperature of the kiln should not be above 115 i^^ 

 The fan and ventilators are usually connected with 

 a thermostat control and the kiln with a recording 

 thermometer. If the temperature rises too high, it 

 discolors the casein and reduces its solubility. 

 Rotary dryers and vacuum dryers are also used con- 

 siderably for drying casein. 



Casein is used in the making of certain glues, 

 paints, papers, textiles and prepared foods. It is 

 also used for imitation ivory, horn, etc. 



Milk Sugar. 



Milk sugar is manufactured as follows: Whey, 

 obtained from commercial casein plants or cheese 

 factories, is acidified and heated to its boiling point 

 in large vats, in order to precipitate the albumin. 

 The solution is then treated with calcium hydroxide 

 and evaporated in a vacuum pan until it forms a 

 syrup. It is then filtered and evaporated again at 

 about 100° F. to a thick syrup, which is removed, 

 placed in shallow containers and cooled. After one 

 or two days it has crystallized into the crude yellow 

 sugar. It is then placed in a centrifugal machine 

 provided with sieves and washed to remove impuri- 

 ties. The washed crystals are redissolved in hot 

 water and treated with chemicals. The clear liquid 

 is then heated to about 170° F. and filtered through 

 charcoal to remove coloring matter. It is now con- 

 densed to a solid mass in a vacuum pan, which is 

 washed and dried on racks in a drying room in which 

 a temperature of approximately 140° F. is main- 

 tained. When dry it is powdered and packed for 

 shipment. 



