286 MILK, BUTTER, AND CHEESE [chap. 



acid. In the making of softer cheeses like Stilton, the 

 curd is formed at a lower temperature and is not allowed 

 to contract so much in the whey, but is removed and 

 placed in the cheese moulds when still in a soft condition 

 and before it has developed much acidity. In all cases, 

 however, the curd, when it has reached its appropriate 

 consistency, is packed into tin vessels lined with a thin 

 cloth, and perforated at the sides to allow of the 

 expulsion of the whey. At this stage, too, a certain 

 amount of salt is usually mixed with the curd. In 

 making Cheddar cheese, a considerable pressure is then 

 applied to the curd in the moulds, and this pressure is 

 continued two or three days until the mass is thoroughly 

 consolidated. In the softer cheeses no pressure is 

 applied, and the mass of curd has to consolidate by its 

 own weight. The cheese is now made and is a soft 

 mass possessing a slightly sour flavour, the true cheese 

 flavour is only developed during the ripening. The 

 ripening processes which cheese undergoes are extremely 

 various, thus giving rise to the special and very distinct 

 flavours which the different kinds of cheese possess. 

 We may distinguish three distinct processes going on. 

 I. Certain enzymes contained in the original milk 

 attack the casein and gradually soften or even liquefy 

 it, breaking it down into a number of simpler nitrogen 

 compounds of the amino-acid type, some of which are 

 strongly flavoured. 



2. Though the lactic acid bacteria die out, other 

 bacteria develop, and some of them form highly 

 characteristic flavouring products out of the casein or the 

 butter fat. In some case special bacteria are introduced 

 into the curd, as in the making of Gruyere, Dutch, and 

 Roquefort cheeses. Sometimes the bacteria associated 

 with the special flavour of the cheese also give rise to 

 gas, and blow round holes in the cheese, as in Gruyere. 



