Rennet tablets are white, powdery tablets that are wrapped in foil, boxed and sold for use in cheese making and other recipes. They are usually found near the pudding section in the grocery store or available online. Junket is a popular brand of rennet tablets.

Ancient people might have discovered rennet by storing fresh milk in a bag made from the stomach of a young animal, such as a lamb or calf, and discovering that the milk was changed into creamy lumps (called curds) and a liquid (called whey). Being adventurous souls, they tried the curds and whey and found that they were edible and perhaps even tasty. At any rate, the process preserved the milk so that it did not spoil so quickly. Humans soon realized that something in the lining of the fourth stomach of suckling animals caused this curdling effect and began to use this substance, called rennet.

There are three types of rennet. The first is the traditional animal type, which is most often made from the stomach of suckling calves. It is the type often preferred by small homestead and artisanal cheese makers. The second type is vegetable rennet, made from mold. This type is preferred by vegetarians. The third type, chymosin rennet, is produced from genetically modified microorganisms. This cheaper rennet is the type used most often in commercial cheese manufacture.

Rennet tablets can be used to make all types of cheese, from the soft cheeses such as cream cheese or cottage cheese to the hard cheeses like cheddar or Swiss. A type of pudding, called junket, is made from rennet tablets. The advantages of using rennet tablets, as opposed to liquid rennet, are that they are easy to divide and measure, widely available and last for several years on the shelf.

Use the freshest milk available when using rennet tablets to make cheese, and carefully follow the recipe’s directions (see Resources). Remember that 1 teaspoon of liquid rennet is equivalent to 1 rennet tablet. Thoroughly dissolve the rennet in cold water before adding it to the warmed milk. Once the dissolved rennet tablet is mixed with the milk, do not disturb it while it coagulates the milk. This can take anywhere from one to several hours, depending on the recipe.

Without rennet, it would be impossible to have the cheese that is so vital to many of the world’s most popular dishes, such as quiche, cheese omelet, cheese fondue, bagels with cream cheese and pizza. Cheese is more easily digestible than milk because the bacteria and enzymes break down the lactose. It is a good source of calcium, protein and other nutrients.