UNITED STATES DEPARTMENT OF AGRICULTURE 
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 BUTT^it 
MILK OR SKIM MILK. 1 
By Arnold O. Dahlberg, 2 of the Dair\ 
CONTENTS. 
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 
Page. 
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-milk 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 
