I just started a new bottle of veal rennet, and it is NOT acting the same as the last bottle I got from the same source. The curds are not firm enough.
Is it possible to have a defective rennet?
Alice
Might be old or damaged from heat exposure.
I've ordered a new one.
Is there some way to test this so I can adjust the 'dosage'?
The way it's done commercially to standardize IMCU/ml is you take a reference rennet (CHR Hansen makes it) and your rennet, and you see how long it takes to coagulate a volume of rennet and a volume of milk. Say, 1 ml rennet and 100 ml milk. Then you do the same for the test rennet and compare the two. There are a few ISO standards that govern all that.
Practically what you can do is measure out something like 1 cup milk and your normal dosage of rennet for 1 cup, and see how long it takes to flocculate. Then adjust the amount you need for the large batch to reach the target flocculation for your cheese type (10-15 minutes for most cheese)
Ok, I did the test with one cup of milk. It set ok.
Maybe I need to add calcium chloride to the goat milk, as it's late in the lactation cycle.