Making cheese is both an art and a science. Cheesemakers rely as much on measurements of pH levels and inoculations of specific molds as they do their own senses of sight, touch, and smell.
There are six important steps in cheesemaking: acidification, coagulation, separating curds and whey, salting, shaping, and ripening. While the recipes for all cheeses vary, these steps outline the basic process of turning milk into cheese and are also used to make cheese at home.
The first step to making cheese is acidification. During this stage, a starter culture is added to milk that will change lactose (milk sugar) into lactic acid. This changes the acidity level of the milk and begins the process of turning milk from a liquid into a solid.
Coagulation is the process of transforming the liquid into a semisolid. When making cheese, an enzyme called rennet is added either as a liquid or paste to further encourage the milk to solidify.
Curds and Whey
As the milk solidifies, it forms curd and whey. The curds are the solid part and whey is the liquid. In this step, the curds are cut using a knife or a tool that resembles a rake.
Cutting the curds further encourages them to expel whey. Generally, the smaller the curds are cut, the harder the resulting cheese will be. Soft cheeses like Camembert or Brie are hardly cut at all. Harder cheeses like cheddar and Gruyere are cut into a very fine texture. For these harder cheeses, the curds are further manipulated by cheddaring and/or cooking. Cooking the curd changes its texture, making it tender rather than crumbly.
When this process is complete, the whey is drained away, leaving the curd alone to become cheese.
Salt is added for flavor. It also acts as a preservative so the cheese does not spoil during the long months or years it spends aging and it helps to form a natural rind on the cheese.