If you make cheese with starter culture and rennet is the whey that is a byproduct of this process safe to drink? I have heard from some that there does exist some who are fond of drinking this but I'm not sure if the whey from rennet is safe?
Whey is an excellent source of protein and whey protein in particular is used in many body-building supplements.
Please see the excerpt below from FARMcurious .
Drink Up! – The acidic tang of whey may be a bit of an acquired tasted but I actually find it refreshing. Cultured whey has pro-biotics that can help balance the microflora in your gut as an extra bonus to the protein.
The web page gives a lot of information about whey and the many other uses for it as well as a great tip for storing.
Hope this helps!