CURD-MAKING 71 



very slowly. The increasing of either the acidity or 

 moisture usually increases the rate of cheese ripening, 

 other factors being the same. 



The relation of the acidity and the moisture is so im- 

 portant that it cannot be neglected without injuring 

 both the quality and quantity of cheese. This knowl- 

 edge can be obtained only by experience. 



94. Setting temperature. The temperature of ren- 

 neting makes very much difference in the texture of 

 the product. The enzyme rennin is sensitive to very 

 slight changes in temperature. Below 70 F., its rate of 

 action is very slow. Beginning with approximately 

 20 per cent of its maximum effectiveness at 70 F. (the 

 curdling point for Neufchatel), it has risen to 65 per cent 

 at 84 F., to 70 per cent at 86 F., as used in Cheddar, 

 to about 80 to 85 per cent at 90-94 F., as used in Lim- 

 burger. At 105 F. it reaches its maximum effective 

 working rate to fall from that efficiency to about 

 50 per cent at 120 F. Curdling at low temperature 

 lengthens the time required for the same amount of ren- 

 net to curdle a given quantity of the same milk. The 

 texture of curd produced at temperatures between 70 F. 

 and 84 F. is soft, jelly-like, friable rather than rubbery. 

 At 86 F. it begins to show toughening or rubbery char- 

 acters which become very marked at 90 F. to 94 F. 

 as used in Limburger. With the increased Vigor of 

 action as it passes its maximum rate of action at 

 105 F., the texture tends to become loose, floccose to 

 granular. Aside from the Neufchatel group, the work- 

 ing range of temperatures for the renneting period 

 runs from about 84 F. to about 94 F., a range of 

 barely 10 F., or the use of 65 per cent to 80 or pos- 

 sibly 85 per cent of the maximum efficiency of the 



