86 
LABORATORY MANUAL 
EXERCISE NO. 9 
Object: To determine the effect of the temperature of the milk on the efficiency 
of separation, and on the amounts of cream and skimmilk, and 
the test. 
Procedure: In purchasing a separator, the following points should be 
considered: 
(1) Number of cows. 
(2) Capacity of the separator. 
(3) Efficiency of skimming. 
(4) Simplicity or ease of cleaning. 
(5) Durability. 
(6) Convenience of obtaining repairs. 
(7) Power to operate. 
(8) Ability of skimming a rich cream without high fat losses. 
(9) Price. 
(10) Ease of oiling—amount of oil needed. 
(11) General construction to promote cleanliness. 
A. Obtain 30 or 40 pounds of milk and divide it into equal parts. 
Skim one part at a temperature of 90° F., flush bowl, and skim 
the second part at a temperature of about 60° F. Follow the 
instruction of Exercise 8 for skimming. 
Note: The class should be shifted so that every member has 
a new position. 
Observations: Machine.No.Capacity. 
(1) Weight of milk . 
(2) Test of milk . 
(3) Pounds of fat . 
(4) Pounds of cream. 
(5) Test of cream .. 
(6) Pounds of fat in cream . 
(7) Pounds of skimmilk . 
(8) Test of skimmilk .. 
(9) Pounds of fat in skimmilk . 
(10) Fat unaccounted for .. 
(11) Per cent cream is of milk . 
(12) Length of test in minutes . 
(13) Capacity . . 
(14) Speed of bowl . 
(15) Temperature of milk . 
Conclusions: 
Questions: (1) How should a separator be washed in order to assure a 
good quality of cream? 
(2) What is the effect on the strain of a separator bowl if the speed 
is doubled? If the diameter is doubled? 
(3) How should cream be cooled in order to insure a good quality? 
(4) Describe the construction of a typical cream cooling tank. 
References: Jud. pp 180-192; St. pp 224-236. 
