42 



curd is allowed to settle on the bottom of the vat with only an occa- 

 sional stirring until a certain amount of free paracasein is formed by 

 the action of more lactic acid (references No. 3, p. 78, and No. 8, p. 57). 

 There are special forms of apparatus that may be used in stirring 

 curd (reference book No. 8, p. 59). 



7. Acidity of whey in regulating heating. — If the first whey con- 

 tains about 0.11 per cent of acid, the acid will form slowly and the 

 curd should be heated more gradually. If the whey contains 0.18 or 

 0.14 per cent of acid, the curd can be heated more rapidly. 



[Suggestions to lecturer: In the first stages of cheese making there 

 is needed great care in developing an acute sense of observation, not 

 only of sight but of touch. These can be acquired only by actual 

 experience under the guidance of a trained teacher. In the condition 

 of curd at time of cutting and in the gradual changes of pieces of curd 

 from very soft to tough condition there is opportunity for the very 

 closest training in observation.] 



EXPERIMENT AND PRACTICE WORK, EIGHTH LECTURE. 



Time required. — Two to four hours should be given to the work. 

 Apparatus required. — The apparatus is the same as for the preceding 

 lecture and in addition curd knives. 



1. Go through operation of cheese making from start either with 

 10 or 20 pounds of milk in a pail or with 100 pounds or more in a small 

 vat. Make special study of indications that tell when to cut curd. 



2. The use of curd knives can be learned only by use in a vat. Prac- 

 tice using the knives carefully according to directions of instructor. 



8. Stir curd after cutting with care, and constantly study the 

 appearance of the curd in order to learn when to apply heat. 



4. Apply heat according to directions, watching the changes that 



take place in the curd. 



NINTH LECTTmE. 



REMOVING WHEY FROM CURD AND CHEDDARING THE CURD. 



1 . When to remove whey from curd. — The whey should be removed 

 from curd when lactic acid has caused the formation of certain amount 

 of free paracasein or when there is "enough acid on the curd," as the 

 cheese maker commonly says (reference No. 3, p. 73, or No. 8, p. 

 61). The whey should be removed very promptly when the time 

 comes and the curd thoroughly drained. 



2. How to ascertain when there is acid enough. — Several indications 

 show when the whey should be removed from the curd, (1) The 

 pieces of curd should be contracted to less than one-half their original 

 size. (2) They should be firm and rubber like, so that when a mass 

 of curd is pressed between the hands and then suddenly free(1 from 

 pressure the pieces should fall apart at once and show no tendency to 



