CHEDDAR CHEESE 309 



cut, it is important that the little cubes do not stick together 

 again, since this would prevent the escape of the whey. In 

 order to keep them separate, the curd should be stirred gently 

 as soon as the surface film has become strong enough to pre- 

 vent their being broken. At first, this stirring must be very 

 gentle, but can become more vigorous as the cubes contract 

 and become firmer. Breaking the cubes will result in an 

 increased loss of fat and casein in the whey. 

 Heating the curd. 



The chief purpose of the cheese-maker at this stage is to 

 extract the whey from the little cubes of curd. This process 

 can be hastened by heating or "cooking" the curd, a term 

 which is somewhat misleading since the temperature applied 

 is never sufficient to in any sense cook the curd, the purpose 

 being simply to assist in the contraction of the cubes and the 

 expulsion of the whey. The escape of the whey is probably 

 due to the combined action of the rennet, the lactic acid, and 

 the heat. The amount of heat to be applied, therefore, will 

 be dependent on the first two factors, and it should be applied 

 very gradually in order that it may penetrate the curd and 

 avoid uneven heating. Ordinarily, the temperature should not 

 be raised more than 2° F. in five minutes, and under some condi- 

 tions it should be even slower than that. If heated too rapidly, 

 the surface film of the cubes becomes too thick and prevents 

 the escape of whey. Usually, the temperature should be raised 

 to 96-100° F., but, under certain circumstances, a somewhat 

 higher temperature may be required. The amount of fat in 

 the milk will affect somewhat the degree of heat, to be applied ; 

 other things being equal, milk rich in fat will require a higher 

 temperature to accomplish a given result. At the close of the 

 cooking process, the cubes of curd should be shrunken to less 

 than one-half their original size and should be firm and rubber- 

 like in texture. At this point, if a mass of curd is pressed firmly 

 in the hand and then suddenly released, the cubes should fall 



