DAIRYING 49 



after which the salt containing no lumps is added ; then revolve 

 the churn six times and let it stand a few minutes to drain off 

 the surplus water; revolve again four times and let stand five 

 minutes, then repeat this working, with short intervals of drain- 

 ing, until the salt is dissolved and evenly distributed through 

 the butter. A little practice and careful observation of results 

 will soon determine the number of revolutions and intervals best 

 adapted to give satisfactory results with each churn. 



It is not, however, a machine that can be successfully used 

 by a careless workman, as it is more complicated than a table 

 worker and requires judgment in running it and some knowledge 

 in arithmetic for calculating the amount of salt and color to be 

 used in each churning. 



622. It is true that different lots of butter varying in salt 

 content can not be easily obtained from one churning for different 

 customers, but the total amount of butter in each case can be 

 calculated from the weight and test of the milk or cream and 

 sufficiently accurate figures obtained for determining the amount 

 of salt and color used for each churning of butter. 



The combined churn is not an automatic machine that will 

 do satisfactory work by simply pulling the lever or shifting a 

 belt and then leaving it to run, but its operation must be watched 

 and regulated. One thing that is especially necessary to be sure 

 of and that is to see that all the butter passes through the rollers 

 the same number of times, and that some of it does not escape 

 them. When this is the case the butter will be unevenly worked 

 and may be mottled. Such a possibility may be easily avoided 

 by not attempting to work more butter than the churn is built 

 to handle and by inspecting it occasionally during the working. 



623. In warm weather when the butter is apt to be soft, ice 

 may be placed on the rollers and the door closed, thus confining 

 the cold from the ice in the churn until the butter has hardened 

 when the ice may be removed and the working finished. 



