518 MANUAL OF MILK PRODUCTS 



freezes, coarse spines or crystals will be produced. The moment 

 it freezes thoroughly it becomes brittle and, instead of holding 

 more air, it slowly gives up that which it has already taken on, 

 or, in other words, it "beats down'' ; hence the colder the cream 

 is made before its removal from the freezer, assuming a uniform 

 rate of speed for the dasher, the smaller will be the yield. The 

 best temperature for withdrawal seemed to be 28, even though 

 at this temperature the product was thin enough to pour like 

 heavy gravy or condensed milk. Those creams with which the 

 greatest swell was obtained required the longest time to cool 

 through to the 17 or 16 of holding temperature. The cream 

 does not swell at first, unless it is put into the freezer at not 

 above 34 in temperature. Hence it is folly to run at a high 

 rate of speed at the outset, and may even cause damage by 

 partially churning the cream before it cools to a point below 

 the churning temperature. When the speed is controllable, a 

 slow initial movement followed by a rapid one when the cream 

 reaches the whipable point, and, finally, a speed slowed down to 

 prevent loss of swell while finishing off or carrying the cream 

 from 29 to 28, or from 28 to 27, seems to be the best proce- 

 dure. If this can be done carefully enough it may be hardened 

 to 26 before removing from the freezer. 



The amount of fat in the cream has little or nothing to do 

 with the amount of air which may be incorporated ; but it has 

 much to do with the amount which remains incorporated. A 

 skim-milk can be made to swell 100 per cent or even more ; but 

 the product is coarse and the result only a temporary one, for 

 it quickly loses its air and falls or sinks in the can. 



In order to whip \vell and to remain whipped, a cream should 

 contain from 18 to 22 per cent fat, should be twenty-four hours 

 old as cream, and should be cold. A cream containing 35 to 

 40 per cent is too soggy to whip well and affords only a poor 

 increase. The per cent of swell obtained is based on the amount 

 of "mix, " and not simply on the amount of cream before sugar is 



