Rennet is a tablet or liquid that contains enzymes used in the cheese making process. One rennet tablet can coagulate 5 gallons of milk. Rennet can be derived from animal or vegetable sources.
See Read More link for detailed information. Junket brand rennet is available in many grocery stores as well as Walmart (check the isle with gelatin products). Rennet tablets can be stored for up to 5 years if stored in the freezer.
We recommend New England Cheese Making Company as an excellent source of cheese making supplies and information.