64 SCIENCE AND PRACTICE OF CHEESE-MAKING 



can take the place of starters in hastening the ac- 

 tion of rennet, and, to some extent, in the subse- 

 quent stages. While it is possible to assist the lactic 

 acid bacteria in this way, great caution is required. 

 The addition of too much acid results in the produc- 

 tion of cheese that does not ripen. So far as we 

 know, the application of artificial acids in cheddar 

 cheese-making has never been worked out to such 

 an extent that all details are under control. While 

 cheese of good quality can be made in this way, there 

 is probably no advantage, even when the process is 

 under absolute control; and, in the absence of such 

 control, no one should ever attempt to employ such a 

 method in practical work. 



USE OF PEPSIN IN CHEDDAR CHEESE- 

 MAKING 



Commercial pepsin prepared from the stomachs 

 of sheep has been successfully used in place of ren- 

 net-extract in making cheddar cheese. The special 

 pepsin most used in this way is a scale-pepsin 

 known as 1-3000 strength. Five grams of this pep- 

 sin equal the coagulating power of 3 ounces of 

 Hansen's rennet-extract. The pepsin is dissolved 

 in cold water for use. In using pepsin, one should 

 make a solution and test it in comparison with ren- 

 net-extract on the same milk. (Modern Methods 

 of Testing Milk, etc., pp. 125-126.) Pepsin has the 

 following advantages over rennet-extract: (i) It 

 is more concentrated and, therefore, more conven- 

 ient and less expensive to ship. (2) If kept dry, 

 pepsin retains its strength indefinitely, while ren- 

 net-extract does not. These advantages of pepsin 



