282 BUTTER-MAKING. 
tion. A small variation in the components of butter affects 
the quality very little, provided the butter has been properly 
made, and the components properly incorporated. In the 
same creamery the composition of butter varies according to 
the season of the year, from day to day, and even from one 
churning to another. According to the present methods of 
manufacture, water, salt, and fat are the components most 
likely to vary. Casein varies very little. 
Curd and Sugar.—Occasionally the curd-content may go as 
high as 4%. It rarely exceeds 2%, and seldom falls below .5 
of 1%. A high curd-content will show itself in the butter in 
the form of a milky brine, or in the form of white specks. If 
there is less than 2% 0” curd present in the butter, the brine 
shows no noticeable milkiness. More than that much curd 
can, as a rule, be detected from the color of the brine. 
If the casein or the curd has been incorporated in the form 
of small lumps or specks, then abnormal amounts of curd 
appear. When the sample of butter is taken for analysis, such 
a speck of curd present in the sample raises the final curd-con- 
tent to a comparatively high figure. 
As has been mentioned before, the curd and milk-sugar are 
incorporated from the buttermilk into the butter during the 
churning. In manufacturing butter for storage, these sub- 
stances should be excluded from the butter as thoroughly as 
possible. The milk-sugar and albuminoids constitute the chief 
food for bacterial growth. As the deterioration of butter has 
been demonstrated to be due chiefly to the action of organisms, 
it becomes essential to restrain their growth as much as possible 
by excluding food necessary for their growth. 
Salt.—In the chapter discussing the salting of butter, it was 
mentioned that a small increase or decrease in the salt-content 
of butter can be recognized by most consumers, while the same 
variation in the other constituents cannot be noticed so easily. 
The average salt-content of butter is about 2%. As the amount 
of salt properly dissolved in butter depends upon the amount 
of water present, the first important step in controlling the salt- 
