MANUFACTURE OF CASEIN. 
25 
only handled as easily as that precipitated with sulphuric acid but is 
not nearly so tough nor so hard to grind. 
COMPARISON OF THE DIFFERENT METHODS OF MAKING SKIM-MILK CASEIN. 
The quality of casein made by the ejector method is superior in 
many ways to that made with the acid and cooked-curd methods. 
It shows better strength, dissolves more readily, and retains a fluid, 
viscous body at room temperature, giving it better working prop- 
erties. When dissolving acid and cooked-curd casein, complete solu- 
tion is retarded by the formation of a heavy, short, viscous body, 
which upon cooling has a decided tendency to congeal and lose its 
fluidity, more especially the cooked-curd casein, making it very 
difficult to mix well with other solutions in the cold. Table 4 shows 
the comparative strength of casein made from the same lots of skim 
milk with the ejector, acid, and cooked-curd methods. 
Table 4. — Comparative strength of skim-milk casein made with ejector, acid, 
and cooked-curd methods. 
Skim milk. 
Times 
curd 
washed. 
Acidity 
of drain 
water. 
Drying 
temper- 
ature. 
Method. 
Casein 
required. 
Lot No. 
Portion 
No. 
56.25 
56.25 
56.33 
56.33 
56.34 
56.34 
56.59 
56.59 
56/59 
56.60 
56.60 
56.60 
56.61 
56.61 
56.61 
56.89 
56.89 
56.89 
56.90 
56.90 
56.90 
25A 
25 B 
33A 
33 B 
34A 
34 B 
59A 
59B 
59C 
60A 
60B 
60C 
61A 
61C 
61 D 
89A 
89B 
89C 
90A 
90 B 
90C 
1 
4 
1 
4 
1 
4 


3 


3 


3 
1 
1 
3 
3 
1 
3 
Per cent. 
0.38 
.10 
.22 
.00 
.14 
.02 
° F. 
130 
130 
130 
130 
130 
130 
130 
130 
130 
128 
128 
128 
130 
130 
130 
124 
124 
124 
124 
124 
124 
Sulphuric acid. 
Ejector 
Sulphuric acid. 
Ejector 
Sulphuric acid. 
Ejector 
Sulphuric acid. 
Cooked curd.. 
Ejector 
Cooked curd.. 
Sulphuric acid. 
Ejector 
Sulphuric acid. 
Cooked curd.. 
Ejector 
Sulphuric acid. 
Cooked curd.. 
Ejector 
Sulphuric acid. 
Cooked curd . . 
Ejector 
Grams. 
9 
8+ 
9 
8 
8 
8 
10 
9+ 
8 
9 
8 
9 
9+ 
8 
8 
7+ 
8 
7+ 
.01 
.28 
.53 
.25 
.06 
.13 
.10 
.09 
.04 
.06 
In seven out of eight experiments the wax test showed the ejector- 
method casein to be the strongest, while in one lot no difference was 
noticeable. While the difference in strength is not marked in all 
cases, it shows up with such consistency as to warrant fully the con- 
clusion that the ejector casein is stronger when made under proper 
conditions. The increased strength of the ejector-method skim-milk 
casein and its much better working properties make it the most 
desirable from the standpoint of quality. The ejector method requires 
more vat capacity, as the skim milk has to be held until it has 
developed a sufficient degree of acidity to bring about a firm coagu- 
