CHEDDAR CHEESE-MAKING 199 



temperature, the least amount of steam possible should 

 be allowed to pass through the valve. This should 

 raise the temperature very gradually. If heat is applied 

 too quickly at first, it will cause the curd to lump. A 

 safe rule is to raise the temperature one degree in the 

 first five minutes after the steam has been turned on. 

 The heating should progress slowly until the whole mass of 

 curd in the vat has reached a temperature of 90 to 92 F. 

 The usual temperature to which the curd is heated or 

 cooked is 98 F. to 100 F. The lower the temperature 

 that can be used and properly firm the curd, the better 

 will be the body of the cheese. If the curd is heated too 

 high, it will become hard, which causes a dry hard 

 "corky" cheese. After this temperature has been reached, 

 there is not such a tendency for the curd particles to 

 stick together nor are they so easily broken in stirring. 

 It should require, under normal conditions, not less than 

 thirty to forty-five minutes, from the time <the steam is 

 turned on, to raise temperature of the curd from the 

 setting temperature to that necessary to " firm " the 

 curd. If a shorter time is allowed to raise the temperature, 

 the curd will not have opportunity to contract naturally. 

 The temperature required to expel the moisture properly 

 varies with the percentage of fat in the milk. If rich 

 in fat (4.5 to 5.5 per cent) milk requires a temperature of 

 98 to 104 F. to firm the curd, while the same result can 

 be accomplished with milk testing 3.0 to 3.5 per cent fat 

 at a temperature of 94 to 96 F. A higher temperature 

 is needed in winter than in summer because the milk is 

 usually richer in fat. In a water- jacketed vat, allowance 

 must always be made for the rise in temperature due 

 to the water surrounding it. The water may be removed 

 if there is danger of the temperature going too high. 



