636 MILK 



or a piece of tin the protruding ice-cream can be removed from 

 both ends of the tube. Where a continuous freezer is used, the 

 sampler may be held under the spout of the freezer and filled with 

 little difficulty. The sample is transferred from the sampler to 

 the funnel, the stem of which is inserted in the neck of the 250 c.c. 

 flask. In order to readily hold the 50 c.c. of ice-cream the open- 

 ing of the funnel should be 3 inches in diameter. 



"To transfer the ice-cream from the funnel to the 250 c.c. 

 flask it is melted by pouring over it exactly 200 c.c. of hot water. 



"In case a funnel is not available, equally good results can be 

 obtained by transferring the sample of ice-cream to a 250 or 300 

 c.c. beaker. By using the hot water from the 200 c.c. flask it 

 can be melted and then transferred to the 250 c.c. flask. 



"To Reduce the Foam. — All melted ice-cream contains more or 

 less foam which appears in the neck of the flask and must be 

 destroyed before it is filled to the 250 c.c. mark. The foam can 

 be eliminated by introducing a measured amount of ether directly 

 into it. Usually 1 c.c. of ether will suffice. As soon as the foam 

 has disappeared the flask can be filled with water to the 250 c.c. 

 mark. This is best done by means of a buret. 



"How Calculations are Made. — The number of cubic centi- 

 meters of water and ether used to bring the volume up to the 

 250 c.c. mark represents the shrinkage which the 50 c.c. of ice- 

 cream have undergone when melted. Subtracting this shrinkage 

 from 50 gives the original volimae of the mix before freezing. 

 It is then an easy matter to determine the percentage of overrun 

 simply by dividing the number of cubic centimeters of shrinkage 

 by the number of cubic centimeters there were in the original 

 mixture. This can be illustrated as follows : 



c.c. 



Sample used 50 



Ether used to reduce foam 1 



Water used to bring to 250 c.c. mark 15 , 5 



Water and ether used {15 . 5 + 1) 16.5 



Volume of mix before freezing (50 — 16.5) 33.5 



Percentage overrun (16.5 -h 33.5) 49.9 



"Comparison of Results. — The following data, obtained by A. 

 C. Baer, in charge of the ice-cream work at the University of 

 Wisconsin, show comparisons of the results obtained with this 

 method and methods commonly employed : 



AMOUNT OF OVERRUN SHOWN 

 Bv Weight By New Method. 



Per cent. Per cent. 



83.3 83.2 



57.0 57.2 



69.0 68.5 



100.0 100.0 



I'O 119.0 



?8 27.8 



36.0 37.2 



90.0 91.0 



88.0 88.0 



83.0 82.6 



