124 THE CHEMISTRY OF THE FARM. 



heated after cutting, with the view of making it shrink 

 and harden ; the temperature used at this point must not 

 exceed 100° Fahr. The drained and broken curd is next 

 put into a press, to remove more effectually the last 

 portions of whey. It is then pulverised in a mill, salted, 

 again passed through the mill, and is then ready for 

 filling into the frames. Curd when put into the frames 

 should contain, according to Voelcker, about 54 per cent, 

 of water when thin cheese is to be made, and not more 

 than 45 per cent, if thick cheese is manufactured. The 

 curd from skim milk will contain much more water than 

 a curd rich in butter. The frames filled with curd are sub- 

 jected to a gi-adually increasing pressure for several days. 

 The cheese is then removed from the frame and placed 

 in the cheese-room to ripen. 



Cheese ripens best at a moderately warm temperature ; 

 about 70° is a suitable degree of heat. During the opera- 

 tion a loss of water takes place, the loss being greatest in 

 the case of poor cheese. If decay, or a growth of mould 

 occurs, a further considerable loss of weight takes place, 

 the casein and fat of the cheese being decomposed 

 by the organic life thus introduced, while carbonic acid, 

 ammonia, and a variety of other products are formed. It 

 was once believed that fat was produced during the 

 ripening of cheese ; this however is not the case. 



A very rich cheese, as old Stilton, may contain about 

 20 per cent, of water, 44 per cent, of fat, and about 29 

 per cent, of casein. In a good Cheddar or Cheshire 

 cheese we should find about 33 per cent, of water, 33 per 

 cent, of fat, 28 per cent, of casein, and about 3 to 4 per 

 cent, of ash constituents, nearly half of which would be 

 common salt. In skim-milk cheeses the percentage of 



