6 BULLETIN 661, U. S. DEPARTMENT OF AGRICULTURE. 



When all the curd is placed in the cloths heavy pressure is applied 

 by means of jackscrews until the following morning or until the curd 

 is sufficiently dry for satisfactory grinding. In case some one is not 

 at the plant all the time some method for maintaining a continuous, 

 heavy pressure must be provided, as the expulsion of moisture from 

 the curd under pressure quickty releases the tension. A satisfactory 

 device for obtaining such pressure can be made easily and added to 

 the regular press rack by means of heavy railway-car springs. When 

 pressure is first applied to the curd a little attention is necessary to 

 get the curd to press evenly; afterwards the jackscrews have to be 

 tightened only occasionally. 



GRINDING. 



Provided the pressure has been ample, no trouble will be experi- 

 enced the following morning in properly grinding the curd. The 

 curd should not be taken from the press until it is sufficiently dry 

 for proper grinding and drying. In this condition grinding pro- 

 duces a fine, mealy curd that spreads well and does not adhere in 

 lumps to prevent favorable drying conditions. When sufficient mois- 

 ture has not been pressed from the curd, serious difficulties are ex- 

 perienced, as it is extremely hard, if not impossible, to grind a wet, 

 soggy curd. After grinding, the curd must be dry and mealy, so 

 that it may be spread easily upon the drying trays and permitted 

 to dry thoroughly and quickty. Ground curd, if wet, can not be 

 spread satisfactorily, and not only adheres in lumps that are very 

 difficult to dry, but in drying they form a hard, impervious, bonelike 

 outside surface, while the interior still remains mcist. 



The curd should be ground fine enough to allow it to dry rapidly 

 and thoroughly. The importance of the thorough pressing and 

 grinding' of the curd can be appreciated readily when consideration 

 is given to the following factors: 



Steam for drying is saved. 



Finely ground curd sdves a lighter colored and much better looking grade 

 of casein as it comes from the drying tunnel. 



The curd requires a shorter period of heating. 



More curd can be handled in a given time, thus increasing the efficiency of 

 the plant. 



There is less wear and tear on tbe machinery. 



PI. ACI.xo Tin: GROUND CURD ON THE DRYING TRAYS. 



A fine-mesh screening must be used for the drying trays, as the 

 buttermilk casein is very fine and not flaky like that made from skim 

 milk by the addition of commercial acid. The finely ground curd is 

 most easily spread upon the drying trays shortly after grinding. 

 While the work can be done by the usual method of throwing a 

 shovelful of the ground curd on a tray and then spreading it with 



