I've been making and using rennet made from my own calves and goat kids for several years following Fankhauser's methods somewhat closely (cleaning the abomasum with a minimal amount of water, then packing in lots of salt and keeping at curing temperatures for a few days, then drying in the dehydrator overnight at 95F, then storing in the freezer, then soaking a piece in whey left over after making ricotta for about 24 hours before using the whey for rennet), but some recent issues with some kind of early stage gas production in some of my cheeses has me wondering whether my rennet could possibly be the source of those issues and whether I can just generally improve on how I make and use rennet.
Is it possible to heat rennet to kill or significantly reduce at least some potential bacteria or yeast without deactivating the enzymes? I think New England Cheese Supply says on their website that rennet can stand temperatures up to 140F. I believe beer brewing enzymes are deactivated somewhere around 160F.
Is anyone else making his own rennet and have any recommendations on how best to do it in a low-tech, self-sufficient way?
