How Is Cheese Made?
All cheeses are made in basically the same way: by curdling milk so that it separates into curds and whey. Curds are solid white lumps, and whey is a thin, watery liquid.
To make cheese, milk is first heated to kill any harmful bacteria. After the milk cools, it is put into large containers. A starter culture of special bacteria is then added. These bacteria break down the sugar found in milk (called lactose) into lactic acid.
After the starter culture, rennet is added. Rennet contains an enzyme that makes the proteins in the milk (called casein) coagulate. This makes the milk separate into solids (curds) and liquids (whey).
Once solid curds have formed, they are cut into smaller pieces to release more whey. The mixture is then heated in a process called syneresis to release even more whey.
The whey is then drained off, leaving only the curds behind. The curds will then begin to clump together in a process called cheddaring. Salt is often added at this point to improve taste and remove additional moisture.
The salted curds are eventually pressed into blocks and cooled until they form solid blocks. The solid blocks of cheese are then stored for several weeks to several months to allow them to ripen until they are ready to eat.
Different types of cheeses are made by using different starter cultures or slightly varying the steps of the cheese-making process. For example, mozzarella cheese is kneaded like bread dough to give it its signature stretchy texture.