632 MILK 



ess, so that the finished product occupies a larger space than the 

 original mixture. This increase in volume, known as "swell" or 

 "overrun/' may be as great as 80 per cent. While 1 gallon of 

 French cream is made from 1 gallon of mixture, nearly 2 gallons 

 of American ice-cream are made from 1 gallon of mixture. 



Manufacturers use different formulae for ice-cream mixtures. 

 The chief ingredients in American ice-cream are cream, unsweet- 

 ened condensed milk, milk, sugar, and flavors. In French ice- 

 cream eggs are also used and the mixture is cooked before freezing. 

 This, in reality, is a frozen custard. The total solids in ice-cream 

 are about 35 per cent. After the ingredients are mixed the fluid 

 is kept in a cold room at about 35 F. and is then placed in a freezer. 

 Here it is agitated and frozen to a semisolid consistency. When 

 this stage has been reached the cream is filled into cans and 

 placed in a refrigerator room at about zero F. for a period of 

 twelve to twenty-four hours. The ice-cream ripens here, becomes 

 hard, and the flavors blend. It is then ready for the market. 



The flavor of ice-cream is conditioned by the flavoring extracts 

 added and the fat content. The higher the fat content, the richer 

 the flavor, but beyond a certain limit the fat renders the ice- 

 cream greasy and less palatable. Cream of 22 to 25 per cent, fat 

 is most suitable. Below this amount the taste is lean, and above 

 it the consistency is unfavorably affected. 



The quality of the cream and milk used in making ice-cream 

 is of the utmost importance. The cowy taste of dirty milk or 

 cream is quickly recognized in ice-cream. The acidity of the 

 milk or cream used should never be above 0.25 per cent., expressed 

 in lactic acid. 



Separator cream gives as good results as gravity cream. 

 Homogenized cream is now used in many ice-creams. Homo- 

 genized cream is cream which has been passed through a homo- 

 genizer at a pressure of 3000 to 5000 pounds. The fat globules 

 are dispersed so that they are very small and are difficult to 

 separate even with a separator. A peculiar richness is imparted 

 to the cream by this process, with the result that cream of 16 to 

 17 per cent, fat content can be used and a product obtained which 

 practically equals one made with the usual 22 to 25 per cent, 

 cream. Experience has shown, however, that the addition of 

 10 to 20 per cent, natural cream gives better results than the 

 exclusive use of homogenized cream. 



Some manufacturers add a small amount of salt to the mix- 

 ture, say, \ teaspoonful to the gallon, as this seems to appeal to 

 the palates of many customers. 



Milk and cream used in the manufacture of ice-cream are now 

 frequently pasteurized in order to prevent the possible spread of 



