Cheese is made by curdling the milk of mammals such as cows, goats and sheep. Hundreds of varieties of cheese are produced worldwide and can be divided into two main categories: Fresh and ripened.

The process of cheese making begins by allowing the milk to thicken and separate into its solid (curds) and liquid (whey) components. This process is hastened by the addition of gelling agents, or a souring liquid such as vinegar.

Once the milk has separated, the curds are collected and drained. At this point, the cheese is "fresh" or "unripened." Cottage and ricotta are popular varieties of fresh cheese.

In order to become "ripened," the curds are cured by heating, soaking, or adding bacteria, and then left under specific environmental conditions to "age." As a general rule, the longer a cheese is aged, the harder it becomes.