WHIPPING CREAM 5 



cent butterfat, and was found to be practically constant. Although the 

 whipping bowl has a 5-quart capacity (liquid measure 1 , only one quart of cream 

 was usually placed in the bowl for whipping. The bowl was submerged in ice 

 water thus keeping the temperature of the cream at approximately 40° F. 

 during whipping, without the inconvenience of working in a cold room. 



Since a good whipped cream should have a high degree of stiffness, all samples 

 in this study were whipped to their maximum stiffness. This could readily be 

 done with the type of whipper used without churning the cream. 



The time necessary to whip the cream to its maximum stiffness was measured 

 with a stop watch. The wattmeter reading was recorded at regular intervals. 

 The increase in stiffness during whipping is shown graphically by plotting the 

 motor input in watts against the time. The average watt increase per second 

 is given in the tables. The whipping curve is not a straight line, yet the average 

 increase in watts per second is in most instances sufficiently accurate for com- 

 parison of whipping ability. As the initial stiffness of the cream varied with 

 the viscosity, the total increase in stiffness during whipping is reported rather 

 than the maximum stiffness. 



The overrun, or volume of air incorporated, was determined by weighing a 

 definite volume of cream and an equal volume of whipped cream. The weighing 

 was done on a Torsion balance (sensitivity 13 mg.\ using a Torsion ice cream 

 overrun cup (65 c.c. capacity). 



Data on serum drainage were secured by filling a pint carton (having both 

 ends removed) with whipped cream and placing it on 12-mesh wire screening 

 over the mouth of a funnel. The drainage was collected in a graduated glass 

 cylinder. After 24 hours in the cold room (approximately 38° F.) the volume 

 of drainage was read and its fat content determined by the Minnesota Test. 



The viscosity of the cream was generally determined with the pipette form 

 of viscosimeter at a temperature of 68° F. In the first experiment the Mac- 

 Michael viscosimeter was used. Samples were tempered to 68° F. in a constant 

 temperature water bath, without agitation, and were poured through a 16- 

 mesh wire screen before making the viscosity determination. 



EXPERIMENTAL RESULTS 



Whipping, Separation, and Pasteurization Temperatures 



Since the whipping ability of cream may be affected by the type of whipper 

 employed, it seemed desirable to study some factors which have already been 

 studied by other investigators. The effect of temperature on cream whipping 

 is generally known. However, this experiment was made because the type of 

 whipper may affect the maximum temperature which can be used without 

 reducing the quality of the whip. A 36 percent cream was whipped at varying 

 temperatures and the results are given in Table 1 and Figure 2. It is obvious 

 from this table and figure that the quality of the whip decreased as the tempera- 

 ture was raised above 40° F. With each increment of temperature increase 

 above 40° F., the percentage of overrun and the maximum stiffness of the 

 whipped cream decreased and serum drainage increased. At 65° F. the cream 

 failed to whip. None of the samples churned during whipping, but they were 

 progressively nearer churning as the temperature was raised. The results of 

 this experiment fixed the desirable whipping temperature at approximately 

 40° F. for further studies. 



