64 
LABORATORY MANUAL 
EXERCISE NO. 48 
Object: To become aeguainted with the Benkendorf lest for over-run in ice 
1 cream. 
Procedure: There are now on the market a half dozen or more contriv¬ 
ances for determining the over-run of ice cream directly in 
the freezing room .very rapidly, provided the weight of the 
“mix” before freezing is known, or if a sample of “mix” is kept 
on the over-run tester throughout the process. These con¬ 
trivances are not adaptable for inspectors who desire to obtain 
the over-run of an already frozen mix which they know nothing 
about. For such, the Benkendorf test is used. It is based on 
the principal that when ice cream is melted, the volume of the 
ice cream will shrink to the original volume of the “mix.” 
A. Take a 50 cc. ice cream sampler and immerse in the ice cream 
to be sampled. Allow it to remain there a short time to become 
thoroughly chilled. Withdraw the sampler, and with a spatula 
level both ends of the sampler. Transfer the sample to a 250 
cc. flask by means of 200 cc. of hot water. This can be done 
by using a funnel. Shake with a rotary motion until all the 
ice cream is melted. 
B. By means of a burette containing hot water, the mixture can 
be brought up to the 250 cc. mark. To get rid of the foam add 
1 or 2 cc. of ether. Water is again added to bring the mixture 
to exactly the 250 cc. mark. 
C. The number of cc.’s of water added from the burette plus the 
number of cc.’s of ether represents the shrinkage of the 50 cc. 
of ice cream. The calculations for determining the over-run 
are as follows: 
Let A =the water and ether used in step C, and 50 (volume 
of sampler)—A =B. 
A 
— X100 = % over-run. 
B 
Note: In order that no appreciable error be introduced, it is 
recommended that the 250 cc. flask be wetted and drained 
before transferring the ice cream, in order to compensate for 
the water adhering to the 200 cc. flask. 
Observations: 
Sample 
cc. water and 
ether used* 
50—A 
% over-run 
1 
2 
Conclusions: 
Questions: (1) How may over-run in ice cream be calculated by weight? 
(2) What is considered an average over-run in ice cream? 
(3) What is modified milk, and what are its uses? 
(4) What is the average output of malted milk in the United States 
in one year? 
