CREAMING 93 
rator out of plumb, (3) dirty oil or dirty bearings, (4) 
unstable foundation, or (5) unbalanced bowl. 
C. The best skimming is not possible with any sepa- 
rator when the temperature falls below 60° F. A tem- 
perature of 85° to 98° F. is the most satisfactory for 
ordinary skimming. Under some conditions the cleanest 
skimming is obtained at temperatures above 100° F. The 
reason milk separates better at the higher temperatures is 
that the viscosity is reduced. 
D. Sudden heating tends to increase the loss of fat 
in skim-milk. The reason for this is that the fat heats 
more slowly than the milk serum, which diminishes the 
difference between their densities. When, for example, 
milk is suddenly heated from near the freezing tempera- 
ture to 85° F. by applying live steam, the joss of fat in 
the skim-milk may be four times as great as it is under 
favorable conditions. 
E. Unduly crowding a separator increases the loss 
of fat in the skim-milk. On the other hand, a marked 
underfeeding is apt to lead to the same result. 
F. The higher the acidity of milk the poorer the 
creaming. With sour milk the loss of fat in the skim- 
milk becomes very great. 
G. Sometimes large numbers of undesirable (slimy) 
bacteria find entrance into milk and materially increase 
its viscosity. This results in very unsatisfactory creaming. 
Low temperatures also increase the viscosity of milk 
which accounts for the poor skimming at these tempera- 
tures. 
H. Most of the standard makes of separators will do 
satisfactory work when delivering cream of a richness of 
50%. A richer cream is liable to result in a richer skim- 
