FIRST STEPS IN CHEESE-MAKING 21 



its clean, nutty, mild aroma a nd s harp taste, it should 

 be replaced by a new one. 



Use of starter in cheese-making. — The amount of 

 starter that can safely be used will depend on the 

 amount of acidity or ripeness of the milk at the start. 

 Generally, from 0.5 to 2 per cent is sufficient, but, if 

 the milk is very sweet, as much as 5 per cent can 

 be used. In using- a starter, reject the upper portion 

 and pass the rest into the milk through a fine strainer. 

 If colored cheese is being made, add the starter before 

 the color; otherwise white spots in the curd may be 

 produced. 



Finding proper degree of ripeness. — The proper 

 degree of ripeness can be ascertained by the following 

 methods : • - 



(i) By the use of the test for acidity (p. 4^6) ; ^^^^^^^^r 



(2) by the use of the Marschall rennet-test (p. 429) ; c/ 



(3) by the use of the Monrad rennet-test (p. 431). 



The general aim of ripening is to have such a degree 

 of acidity when the rennet is added that the. curd will 

 remain in the whey not more than 2^ to 3 hours. 

 This time will vary with the seasons of the year, the 

 important point being to have the curd firmed in the 

 whey before too much acidity has developed. Usually 

 when the acid test shows 0^19 to 0.21 per cent of 

 acidity, or when the milk coagulates at 2^ spaces in 

 the Marschall rennet-test, or in 45 to 60 seconds by 

 the Monrad test, the proper degree of ripeness has 

 been reached. Milk testing over 0.21 per cent acidity 

 when delivered at the factory is generally overripe and 

 Hable to cause trouble ; therefore, it should not be ac- 

 cepted, unless most of the other milk delivered at 

 the time has considerably less acidity. 



