180 DAIRY TECHNOLOGY 



upon shelves where small streams of brine play upon 

 them. The brine drains to certain points, is pumped back 

 to the tank, recooled and circulated again. Or the cans 

 may be placed in tanks of brine until the cream hardens. 

 Either style makes a more or less sloppy hardening room, 

 and although the cooling is very efficient, these styles are 

 not being used so widely as the dry hardening room. 



A hardening room which employs the dry system is 

 cooled by ammonia expansion coils. A uniform tempera- 

 ture is maintained and the rapidity of the hardening in- 

 creased by continuous air currents generated by electric 

 fans. 



Standardization of Cream. This topic is treated under 

 " City Milk Supply," but some modifications are necessary 

 when materials other than milk and cream are used. It 

 must be remembered that the sugar, flavoring, etc., added 

 to the cream have similar effects in reducing the percentage 

 of fat as has the addition of skim milk. Therefore, if we 

 add 8 pounds of sugar to 45 pounds of cream containing 

 20 per cent fat, the sweetened cream will contain a con- 

 siderably smaller percentage of fat. 45 pounds of 20- 

 per-cent cream contain 9 pounds of fat; then 53 pounds 

 (45 + 8 = 53) of the sweetened cream contain 9 divided 

 by 53 times 100, which equals 17 per cent fat. Using the 

 formula 45 pounds of cream, 8 pounds of sugar, 4 ounces 

 of flavoring extract, 4 ounces gelatine, to make a ic-gallon 

 batch of ice cream, if the maker wishes his finished product 

 to contain 14 per cent fat, what per cent of fat should he 

 have in his cream? The total weight of materials is 45 

 pounds of cream plus 8 pounds sugar, plus J ounce flavor 

 extract plus J ounce gelatine. This equals 53.5 pounds. 

 If the per cent of fat is 14, or the minimum law standard, 

 this amount of ice cream mix contains 7.49 pounds of 



