36 



7. Effect of dilution hy water upon coagulating power of rennet. — 

 Make, a rennet test of some milk. Dilute portions of this milk as fol- 

 lows: (a) One part of water and four parts of milk; (b) one [)art of 

 water and three parts of milk; (c) one part of water and two parts of 

 milk; and (d) one part of water and one part of milk. Make rennet 

 test of each of diluted samples and compare results. 



8. Effect of salt upon coagulating power of rennet. — Make rennet test 

 of samples of milk. Then to the same milk add salt in amounts equal 

 to 1, 2, 8, 4, and 5 per cent of the milk by weight. Make rennet test of 

 each of these salted samples and .compare results. Try similar experi- 

 ments with common borax. 



9. Ejfect of heating milk upon rennet coagulation. — Make rennet test 

 of some milk. Heat one portion of milk at 160° F. for twenty minutes 

 and another portion to boiling for fifteen minutes. Then make rennet 

 tests again. To some of the boiled milk add a few drops of dilute acid 

 and repeat the rennet test. 



10. Effect of soluble calcium, salts on action of rennet. — Make rennet 

 test of a sample of milk. Add 1 cubic centimeter of a 10 per cent 

 solution of calicum chlorid to the milk and repeat, 



11. Effect of calcium salts on rennet coagulation of heated milk. — 

 Heat a portion of same milk used in experiment 10 to boiling for ten 

 or fifteen minutes. Cool and make rennet test. To another portion 

 add dilute calcium chlorid and make rennet test. 



12. Variation of rennet coagulation in milk of different cows. — Make 

 rennet test on separate milk of each cow of some available herd. 



13. Compare rennet extract ivith 1-3000 aseptic scale pepsin, using the 



pepsin at the rate of one-half gram per 100 pounds of milk (reference 



No. S, pp. 34, 53). 



SEVENTH LECTURE. 



PRELIMINARY STEPS IN MAKING CHEDDAR CHEESE. 



Outline of different steps of operation of cheese making. 



1 . System of keeping records of the operations of cheese making. 



2. First care of milk at the factory. 



3. Ripening the milk. 



4. Adding color. 



5. Coagulating the milk bj" rennet ("setting" the milk). 



6. Cutting the curd. 



7. Heating the curd. 



8. Removing the whey from the curd. 



9. Cheddaring the curd. 



10. Milling the curd 



11. Salting and pressing curd. 



12. Curing cheese. 



1 . System of keeping records of the operations of cheese m,aking. — It is 

 desirable for all cheese makers to keep di.ily records of the details of 



