ICE-CREAM AND ICES 635 



overrun was devised by Benkendorf, and is carried out as fol- 

 lows (Bull. 241, July, 1914, Agri. Exper. Sta. of Univ. of Wis- 

 consin) : 



"The apparatus used in making the test consists of an ice- 

 cream sampler, a 250 c.c. Florence flask, a 200 c.c. Florence 

 flask, a funnel or a 250 c.c. beaker, a buret, and a 1 c.c. pipet. 

 All of these, except the ice-cream sampler, can be readily obtained 

 from any supply house. 



"The ice-cream sampler is a cylinder, about IfV inches in 

 diameter (inside measurements) and about 2J4 inches long, pref- 

 erably made of thin brass tubing. The sampler when filled 



TEMPERATtJRE-SWELL CHART 



Let the space between the lower straight line AA and the upper curved line BJ3 

 represent the space occupied by the mix before, during and after freezing. Let the 

 figures below the lower straight line represent the temperatures of the mix taken at 

 minute intervals during the freezing process. Now, assume that the dasher is being; 

 turned at a uniform rate of speed. Then, distance aa will be the volume of the mix 

 at the temperature 40 and 66 its volume at 34, at about which point the swell com- 

 mences. It will be noted that the increase in volume" continues but slowly at first, 

 but very abruptly after the mass has been beaten at the temperature 29 for about 

 five minutes, reaching its maximum volume, (70% swell) at about the temperature 

 28% or at the point represented by the distance cc- This crest is reached at about 

 the point of thorough freezing. As the temperature falls to 28 the mass begins to 

 become brittle and "beat down" to a point represented by distance dd with 60% swell 

 Jf the beating and hardening processes are continued, the mass will gradually beat 

 down as indicated by the downward curve of the line. This figure is essentially a 

 diagram of averages. 



Fig. 235. (Bull. 155, Vermont Agri. Exp. Sta., September, 1910.) 



should contain exactly 50 c.c. of ice-cream. For testing ice- 

 cream that has been packed and has fully hardened the sampler 

 should be provided with a handle. This type of sampler is also 

 preferred where the ice-cream container has a small diameter. 

 These samplers are open at both ends. The sampler for use 

 with the continuous type of ice-cream freezer or for determining 

 the swell of soft ice-cream is closed at the lower end. 



"Making the Overrun Test. A sample of 50 c.c. of the ice- 

 cream is obtained by pressing the sampler down into the hardened 

 ice-cream until it is entirely below the surface. Allow the sampler 

 to remain there for a moment to get cold and withdraw the sampler 

 and the ice-cream which it contains. By means of a case knife 



