Rennet is a natural enzyme used in the cheese-making process. It helps coagulate milk, causing it to separate into curds and whey. Traditionally, rennet is derived from the stomach lining of young calves, but there are also vegetarian and microbial alternatives available. In addition to cheese production, rennet plays a role in making certain types of desserts and gelatin. Its ability to thicken and stabilize liquids makes it valuable in various culinary applications. Understanding rennet is essential for anyone interested in the science of cheese and dairy products.