Rennet is a set of enzymes that coagulate milk, making it easier to form curds for cheesemaking. Rennet is an important part of any cheesemaker’s toolkit, and it can be made easily at home.
Rennet can be found in several different forms: tablet, liquid and powder. It can also be made from plant or animal sources, and there are many vegetarian alternatives to animal rennet.
Stomach-derived rennet is the most common type of rennet, and it is sourced from young, unweaned calves. This is the only way to guarantee that you are getting a high concentration of the coagulating enzymes (chymosin) that are necessary for cheesemaking.
Vegetarian rennets are not produced from young animals, but can come from a variety of plants that contain the same enzyme as chymosin, including artichokes, nettles, and cardoon thistle. They are more expensive than manufactured rennets, but they offer more predictable results.
A rennet tablet or liquid dissolved in cool distilled or boiled water is sufficient to make a cheese, but it’s recommended that you dilute it to a small amount. This will help it disperse more evenly and provides consistent coagulation.
Non-chlorinated water is essential for cheesemaking, as chlorine messes with bacteria and enzymes. You can purchase distilled water, use a filter, boil and cool your water, or leave it to sit overnight in an open container so that the chlorine naturally dissipates.
Temperature is another key factor for coagulating milk, and it is vital to follow the temperature guidelines in your recipe. If the milk is too warm or too cold, rennet will not coagulate properly and you may end up with a rubbery cheese.
Rennet can be added to fresh, whole milk or a mixture of milk and cream. It is usually mixed in with the milk at the very beginning of the cooking process, and then left to coagulate until the curd is ready for use.
If the cheese is set too quickly, it’s possible that you added too much rennet or culture. It can also be a sign that the milk was not very fresh, so it’s important to make sure it’s fresh before you add it to the pot.
You can also add calcium chloride to a pot of milk, which will increase coagulation. Calcium is a nutrient that binds proteins together and is important for cheesemaking. This is especially true in ultra-pasteurized milk, which undergoes an intense high-heat sterilization treatment.
If you have a lot of trouble achieving a stable curd with your rennet, you may need to add some calcium chloride to the milk. It can be purchased in a variety of different forms, and can keep for an extended period of time in your refrigerator.
