252 MARKET DAIRYING 
time. It is better, however, to avoid an excessive richness 
when an exhaustive churning is to be expected. 
5. Amount of Creamin Churn. ‘The best and quick- 
est churning is secured when the churn is one-third full. 
With more or less cream than this the amount of concus- 
sion is reduced and the length of time in churning cor- 
respondingly increased. 
6. Speed of Churn. The speed of the churn should 
be such as to produce the greatest possible agitation or 
concussion of the cream. Too high or too low a speed 
reduces the amount of concussion. The proper speed for 
each particular churn must be determined by experiment. 
7. Abnormal Fermentations. The slimy or ropy fer- 
mentation sometimes causes trouble in churning by ren- 
dering the cream excessively viscous. Cream from single 
herds may become so viscous as to render churning im- 
possible. At creameries where milk is received from many 
herds very little trouble is experienced from these fer- 
mentations. 
CHURNS. 
A churn is a machine in which the cream is made 
to slide or drop, or is in some way agitated to bring about 
the union of the fat globules, which changes the liquid fat 
into a solid. For many years the factory churns had 
assumed the form of a box or barrel free from any inside 
fixtures. Such churns were revolved by power and did 
very satisfactory work. But it was necessary to transfer 
the butter, after it was churned, to a worker upon which 
it was worked. 
This transfer from one piece of apparatus to another 
was obviated by the invention of “combined” churns and 
