CHEESE. 337 



40 according to Fleischmann), and if the milk be about this 

 temperature the curd is firm and hard, while milk at low 

 temperatures or at about 50, yields soft curd. The more acid 

 the milk the more rapid is the action of rennet. 



In some cases cheese is made without rennet, by simply 

 allowing the milk or cream to turn sour and thus bring about 

 the coagulation of the casein. This method is chiefly used for 

 the preparation of cream cheese. 



Soft cheeses are made by coagulating with rennet at a low 

 temperature (about 25 to 30). They always contain a con- 

 siderable quantity of water. Brie, Camembert, and Neufchatel 

 are types of this class. 



Hard cheeses are formed when the coagulation takes place 

 about 35. 



The quality of a cheese largely depends upon the amount of 

 fat in it. Some hard cheeses are made from enriched milk, 

 i.e., milk to which additional cream has been added. Stilton 

 cheese is an example. 



From lohole milk, Cheddar, Cheshire and Wensleydale, 

 Gruyere, Edam, and Gorgonzola cheeses are made. 



From mixtures of whole milk and skimmed milk, Gloucester, 

 Leicester, and (sometimes) Cheddar, also Parmesan and (often) 

 Edam cheeses are derived. 



From skimmed milk, various poor cheeses, e.g., Limburg and 

 Danish, are produced, but are of little value or importance. 



Koquefort cheese is made from sheep's milk, as are several 

 other varieties/ 1 ' 



The general practice in making a cheese is to hasten the 

 ripening of the milk by the addition of a " starter," consisting 

 of sour milk containing large numbers of the lactic bacterium, 

 or a pure culture of the lactic ferment. When lactic fermenta- 

 tion has proceeded far enough, i.e., when the proportion of 

 lactic acid in the milk reaches a certain amount (determined 

 most safely by titration with standard soda solution, and often 

 about 0-2% lactic acid) it is ready for curdling. By trial with 

 a small quantity of the milk at about 30 the amount of 

 rennet required to cause coagulation in the desired time is then 

 determined, and this quantity is then added to the main mass. 



* Sartori, Jour. Chem. Soc. 1891, abst. 951. 



