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 quickly 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 meaty, so 
that it ma}^ be spread easily upon the drying trays and permitted 
to dry thoroughly and quickly. 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 gives a ligliter 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 the machinery. 
PLACING THE 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 
