42 DAIRY LABORATORY GUIDE 



Revolve churn about ten times and allow to stand 

 for twenty minutes to give the salt a chance to 

 dissolve evenly. Work ten revolutions more, take 

 out, and print or pack in cases or tubs which have 

 been previously scalded and coated on the inside 

 with parafSn at 250° to 260° F. Why? 



In the summer give the Disbrow churn 19 to 20 

 revolutions. In the winter it is necessary to increase 

 it to 25 to 28 in order to give the butter the same 

 amount of working. Where a Victor churn is used, 

 in place of 9 revolutions as in summer, it will re- 

 quire 11 to 12 in .the winter. 



Calculate per cent of overrun as follows: 



Pounds of butter minus pounds of butter fat equals 

 number, pounds overrun. Number of pounds of over- 

 rim divided by pounds of butter fat equals per cent 

 overrun; for example, 800 pounds of butter fat make 

 900 pounds of butter. 900 - 800 = 100. 100 ^ 

 800 = 12J per cent overrun. 



The following blank form may be used for this 

 exercise : 



Date 190... .. 



Pounds butter-fat computed from exercise No. 4 



Estimated pounds of butter 



Pounds of butter made 



Per cent overrun 



Kind and size of churn used 



Temperature of cream in vat 



Time since cooling 



Acid test , 



