236 



MANUFACTURE OF MILK POWDER 



QUALITY OF FRESH MILK 



What has been stated concerning the necessity of a high quality 

 of fresh milk in the successful manufacture of condensed milk, is 

 equally true in the manufacture of milk powder. The fresh milk 

 must be normal in its properties. It must be produced under strictly 

 sanitary conditions and receive the proper care on the farm. It is 

 especially essential that it arrive at the factory perfectly sweet, since 

 acidity tends to lower the solubility of the finished product. 



DESCRIPTION OF THE PRINCIPAL PROCESSES OF 

 MANUFACTURE 



Numerous processes for the manufacture of milk powder have 

 been invented and patented in this country and in Europe. Many 

 of these processes differ but slightly from one another. For con- 

 venience's sake these processes are herein classified in accordance 

 with the fundamental principles of evaporation involved : 



1. The Wimmer Process. The milk 

 is boiled in a vacuum pan similar to that 

 used in the manufacture of condensed 

 milk. The vacuum pan has a deep steam 

 jacket for heating, but in the place of the 

 usual coils, the pan is equipped with a 

 mechanical stirrer. The milk is con- 

 densed at a relatively low temperature 

 and the stirrer revolves until the water 

 content of the milk is reduced to about 

 30 per cent and the milk has become 

 porous and crumbly, though it still forms 

 a compact mass. The drying is then com- 

 pleted in the open air and without addi- 

 tional heating. The product is then 

 ground to a powder. This is the process 

 invented by Ole Bull Wimmer of Copen- 

 hagen, Denmark. 



2. The Just-Hatmaker Process. The milk sprays in a thin 

 film over two steam heated cylinders or drums, about sixty inches 

 long and twenty-four inches in diameter- The cylinders are about 



Fig. 58. The Wimmer milk 

 powder machine 



