124 BUTTER-MAKING. 
draught, and any undesirable taints or odors, since it takes 
about thirty-six hours of quiet standing for the cream to rise. 
If there is a constant current of air in the room, a leathery 
cream is likely to form. At the end of this time the cream is 
removed by the use of a skimmer, made especially for this 
purpose. It is difficult, however, to remove all the cream by 
this means. 
If the conditions are such that cool water can be constantly 
circulated around the pans containing the milk, the tempera- 
ture can easily be made to go below 60° F., and the creaming 
process is facilitated. When such conditions are present, the 
depth of the milk in the pans can safely be increased to about 
6 inches. Under the most favorable conditions about .5% 
fat will remain in the skimmed milk. 
Deep-setting System.—This system is undoubtedly the best 
method of gravity creaming When properly carried on the 
"| fat can be removed so completely that 
no more than .2% of fat remains in 
the skimmed milk. It consists of put- 
ting milk into deep cans (ordinary four- 
gallon shotgun cans are usually em- 
ployed) immediately after the milk 
has been drawn from the cow. Then 
it is put into cold water, and generally 
: cooled down to, and maintained at, a 
Fic. 69.—Cooley creamer temperature of about 55° F. The 
and elevator. . 3 : 
cream will rise in about twenty-four 
hours. Better results can be obtained if the water is cooled 
down to about 40° with the use of ice-water. 
One reason why this system is in use so much, even in 
creamery localities is that the cream obtained is nearly always 
of a good quality. The farmer knows that unless the milk 
be cooled quickly, and maintained at a low temperature, the 
cream will not rise freely. For this reason the milk is syste- 
matically and thoroughly cooled, which is one of the great 
essentials in order to check the growth of the ferments in milk 
