Rennet Tests. 167 
tent it has progressed before the process begins, is 
exceedingly important to the cheese maker. To this 
end, several convenient tests may be applied. The 
veteran, who has attained skill through long manip- 
ulation, can tell with a fair degree of accuracy 
through the sense of smell and taste the amount 
of lactic acid present in his milk, but this is not 
a safe enough guide for those who are inexpe- 
rienced, or those who expect to make a uniform 
product in a uniform 
way from day to day. 
Rennet tests. —The 
percentage of lactic 
acid present in the 
milk ean readily be 
determined directly by 
titration with a stand- 
ard alkali, but the 
amount of lactic acid 
present is also quite 
readily determined 
by the length of 
time required for ren- 
net coagulation, since 
rennet acts more 
quickly upon milk 
the riper it is, and 
upon this fact two 
or three simple tests 
au c b 
have been devised. Fig. 23. Monrad rennet test. a, 5. c. pipette; 
r b, 50 c. e. graduated flask; e, in whi 
The simplest of these ieee Cerne ae 
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