SEMI-HARD CHEESES ' 153 



169. Outline of making Roquefort. Some of the 

 results of these experiments are summarized in the fol- 

 lowing paragraphs : 



Milk. Clean-flavored fresh milk testing 4-4.2 per 

 cent fat and up to 2.8 percent casein gives the best results. 

 The milk with a high percentage of cheese-making solids 

 forms a firmer curd, hence works up better in the process 

 than milk of lower quality. 



Acidity. The milk is ripened by lactic starter up to 

 an acidity of 0.23 per cent titrated as lactic acid at the 

 time rennet is added. This gives a firm curd, which 

 drains to the desired water-content but is low enough 

 to prevent the toughening effect of too high acid. A 

 very slight increase in initial acid 1 to 2 hundredths 

 per cent combined with the rate at which acidity is 

 developing introduces such physical changes in texture 

 as to make the final texture of Roquefort impossible. 



Temperature. Rennet is added at or below 84 F. 

 Every degree of heat adds definitely to the efficiency of 

 rennet. Below 82 F., curdling becomes slower and the 

 coagulum softer and more difficult to drain. The sheep's 

 milk curd is made from 76 to 84 F. but sheep's milk 

 has about twice the cheese solids found in cow's milk. 

 It was found necessary to raise the temperature as high 

 as texture would permit. However, at 86 F. the physical 

 character of the curd tends to become tough or waxy 

 in handling. At 84 F. the curd remains brittle and 

 crumbly. It was, therefore, necessary to keep the cur- 

 dling temperature down to 84 F. 



Renneting or setting. Rennet at a rate of 3 to 4 

 ounces of standard liquid rennet to 1000 pounds (10 to 12 

 c.c. to 100 pounds) was found to give the best curd 

 under experimental conditions. 



