UNITED STATES DEPARTMENT OF AGRICULTURE 



SL&> m <& m ru 



I BULLETIN No. 661 



Contribution from the Bureau of Animal Industry 

 JOHN R. MOHLER, Chief 



Washington, D. C. 



April 9, 1918 



THE MANUFACTURE OF CASEIN FROM BUTTER- 

 MILK OR SKIM MILK. 1 



By Arnold O. Dahlberg, 2 of the Dairy Division. 



CONTENTS. 



Page. 



Importance of casein manufacture to cream- 

 eries 1 



The manufacture of casein from buttermilk. . 2 



Directions for manufacturing 4 



Yield of buttermilk casein 8 



Cost of manufacture 8 



Equipment required 9 



Factors influencing quality 17 



The manufacture of skim-milk casein 22 



Sulphuric-acid method 22 



The manufacture of skim-milk casein — Con. 



Pressed-curd method 23 



Cooked-curd method 23 



Ejector method 24 



Comparison of the different methods of 



making skim-milk casein 25 



Yield of skim-miik casein 26 



Requirements for good casein 26 



Methods of determining quality of casein 28 



Casein markets and prices 31 



IMPORTANCE OF CASEIN MANUFACTURE TO CREAMERIES. 



The utilization of by-products by a large number of small cream- 

 eries is daily becoming of more economic importance. Because of 

 the ever-increasing competition, the future success of many cream- 

 eries depends in no small degree upon both the quality of their prod- 

 ucts and the extent to which by-products may be profitably utilized. 

 The small creameries usually receive a good quality of raw material 



1 Acknowledgment is made of the courtesy of the Robert Gair Co., Brooklyn, N. Y., 

 and the Dill & Collins Co., Philadelphia, for hearty cooperation and assistance in run- 

 ning coating tests on their large commercial machines, which involved considerable in- 

 convenience and expense, but gave valuable information as to the practical value and 

 working properties of the samples submitted. Special thanks are extended to Ernest 

 Hafele and H. A. Sawyer, chemists for the companies mentioned, for their patience and 

 interest in arranging for the various tests and for making it possible to obtain informa- 

 tion relative to the application of casein in the paper industry. 



The J. A. & W. Bird & Co., Boston ; the Casein Manufacturing Co., New York, and 

 the Union Casein Co., Philadelphia, furnished information and data which were of great 

 value in the work. 



In the earlier part of this investigation the Bureau of Standards of the Department 

 of Commerce kindly placed at our disposal equipment for investigation on the solubility 

 of casein, and the assistance of F. C. Clark of that bureau in this connection was of 

 value. 



2 The investigation of the manufacture of casein from buttermilk was begun by Dr. 

 F. J. Birchard, formerly of the Dairy Division, and after his departure the work was 

 taken up by the writer. 



39637°— 18— Bull. 661 1 



