What is rennet?

Rennet is an enzyme that is indeed found in the stomach lining of calves and other young ruminants. It plays a crucial role in the cheese-making process by helping to curdle milk. When rennet is added to milk, it causes the milk proteins, particularly casein, to coagulate and form curds, separating from the whey. This process is essential for creating various types of cheese, making rennet a fundamental ingredient in traditional cheese production.

In contrast, the other options do not accurately describe rennet. Herbs can be used in cheese-making to flavor the final product, but they do not play the role that rennet does in curd formation. While some types of milk may be used for cheese, these do not pertain to what rennet is. Lastly, rennet is not a flavoring agent; instead, its primary function is to facilitate the physical transformation of milk into cheese.