284 MILK, BUTTER, AND CHEESE [chap. 



be removed by any subsequent working. What visible 

 water there is in butter has been left in through 

 imperfect work on the butter table. Well-made butter 

 should not contain more than 15 per cent, of water, 

 though as much as 18 may be not unfrequently found. 

 In addition to the water a certain amount of curd, i.e., 

 coagulated casein, and of lactose derived from the cream 

 serum, are always present, together with whatever salt 

 has been added to the butter in the process of making 

 up. From this account it will be seen that no chemical 

 action takes place during the making of butter ; it is a 

 mechanical process whereby the fat globules are made 

 to coalesce by being beaten together until the surface 

 layer which prevents them from uniting in milk has 

 been broken down. Success in churning depends upon 

 obtaining the right degree of acidity at starting, and then 

 working at the proper temperature. In the further 

 treatment of butter, cleanliness is the chief essential. 



Cheese 



The process of cheese-making is much more elabor- 

 ate than that of making butter. Moreover, from the 

 very large number of different kinds of cheese whose 

 characteristics are developed by special methods of 

 making and curing, it would be beyond the scope of 

 this book to discuss the working details of the processes 

 which result in any particular cheese ; instead, it will be 

 sufficient to consider very broadly the principles involved 

 in the making of one variety, Cheddar, because these 

 principles apply to all other cheeses. Cheese-making 

 may start with either whole milk, separated milk, or 

 milk from which a portion of the cream has been 

 removed ; but it is desirable that the milk should be 

 derived from Ayrshires, Shorthorns, or Dutch cows, 

 which do not give rise to large globules of fat readily 



