41 



3. How to cut curd. — In cutting; curd uniformity in size of pieces of 

 curd must be the object. Two knives of spcM-ial (hvsign are used in 

 cutting curd. One is the horizontal knife with numerous parallel 

 blades; the other, the perpendicular. Makers differ somewhat in their 

 way of using these knives. The following directions should be fol- 

 lowed: (1) Use horizontal knife first. (2) Insert carefully into curd 

 at one end of vat. (3) Do not jam or smash the curd in inserting 

 knife. (4) Move the horizontal knife quietly and firndy from end to 

 end of the vat until it has passed tlu-ough the whole mass of curd. 

 (5) Then use perpendicular knife at once. (6) Cut not only length- 

 wise the vat, but also crosswase. (7) Toward the end of cutting move 

 the knife somewhat more rapidly. In overripe milk the curd should 

 be cut into smaller pieces. The fineness is governed largely by the 

 number of times the knives pass through the curd (reference No. 8, 

 p. 55). 



4. Effect of fineness or coarseness of curd. — Cutting curd fine has the 

 effect of releasing the whey more rapidly and completely and results 

 in a cheese containing less moisture. Coarse cutting causes the slower 

 escape of whey and produces cheese wath a higher moisture content. 



5. Stirring curd after cutting. — The curd if allowed will settle to the 

 bottom of the vat after cutting and mass together again, thus pre- 

 venting the proper escape of the whey. To prevent this massing the 

 curd must be kept in motion, very gentle at first, while the curd is soft. 

 The curd must be kept from settling in the corners of the vat or stick- 

 ing to sides. The whey should be clear and quite free from particles 

 of floating curd (references No. 3, p. 73, and No. 8, p. 57). The curd 

 contracts and hardens on surface during stirring, so that pieces do 

 not stick together so easily. The hardening retards escape of whey, 

 and heat must be used to keep whey from going out of curd. 



6. When to apply heat.~The heating or ''cooking," improperly so 

 called, should begin as soon as the pieces of curd contract and harden 

 on the surface. The cause of the shrinkage is probably due in part to 

 the action of lactic acid upon the calcium paracasein of the curd, the 

 calcium being combined with the lactic acid in forming free para- 

 casein, a compound that has the property of contracting. Heat favors 

 the formation of acid, and its action upon the calcium paracasein of 

 the curd. The heat should be applied gradually and the stirring con- 

 tinued constantly. Under normal conditions the heat is applied so 

 as to raise the temperature of the curd and whey 1° F. in five minutes 

 and rarely more than 2°. The heating should be somewhat slower 

 up to 90° F. than above that point, because the shrinking of curd and 

 expulsion of whey take place less rapidly below than above 90° F. 

 The heating should be carried up to 98° F. The curd becomes less 

 tender as the temperature increases and toward the last can be stirred 

 very vigorously without harm. When 98° F. has been reached, the 



