BUTTERMAKING 251 
This is so because of the differences in the relative amount 
of “soft” and “hard” fats of which butter fat is composed. 
When the hard fats largely predominate the butter fat 
will of course have a high melting point. Such fat may be 
quite hard at a temperature of 60° while a butter fat 
of a low melting point would be comparatively soft at 
this temperature. For a study of the conditions that 
influence the hardness of butter fat the reader is referred 
to the discussion of the “insoluble fats” treated in the 
chapter on milk. 
3. Acidity of Cream. This has a marked influence on 
the churning process. Sour or ripened cream churns with 
much greater ease than sweet cream because the acid 
renders it less viscous. The ease with which the fat 
globules travel in cream becomes greater the less the 
viscosity. Ripe cream will therefore always churn more 
quickly than sweet cream. Ripe cream also permits of a 
higher churning temperature than sweet which is of great 
practical importance where it is difficult to secure low 
churning temperatures. 
4. Richness of Cream. It may naturally be inferred 
that the closer the fat globules are together the more 
quickly they will unite with the same amount of concus- 
sion. In rich cream the globules are very close together 
which renders it more easily churnable than thin cream. 
The former can therefore be churned in the same length 
of time at a lower temperature than the latter. 
The ideal richness lies between 30% and 35%. A 
cream much richer than this will stick to the sides of the 
churn which reduces the amount of concussion. The addi- 
tion of water to the churn will overcome this stickiness 
and cause the butter to come in a reasonable length of 
