Cheese can be roughly defined as a coagulated milk product. It is made by introducing bacteria or enzymes into milk to separate the actual curds (milk solids) from the whey (liquids). Cheese can come from whole or skimmed milk, cream, or any mixture of the two.
The milk to make the cheese can come from cow, sheep, goat, or other animals, such as buffalo. Ripening is the technical term used to change the curds that have separated from the milk and/or cream by adding bacteria or mold to make the cheese the particular variety it is, and each cheese has a specific recipe.
Cheese can be highly processed or simply fermented. While high in proteins, cheese can be low or high in fat, and low or high in water content. The lower the percentage the water, the harder or firmer the cheese is. The higher the percentage the fat is, the higher the solids found inside. Double-crème and triple-crème cheeses are cheeses with a high fat content. They may be as much as 60% to 75% fat content, which means that the cheese has 60-75% fat if all the liquid or moisture inside is removed from it.
Aged cheese has more pronounced flavours, and in most cases has a depth of colour, flavour, and aroma not found in the young cheeses of the same variety. Aged cheeses may also be softer or firmer than the younger counterparts. In most cases, the more aged a cheese is the longer the life: the longer you can keep the cheese. Fresh cheeses are typically stored for a shorter period of time and consumed quickly (cottage cheese has a short shelf life). Hard grating cheeses, if kept whole with the rind uncut, can keep for many months.
Cheese is one of the few culinary food items that can be served as an appetizer, dessert, topping, garnish, accompaniment, ingredient, or the main dish. Cheese served on its own (cheeseboard) is more often than not served at room temperature. Exceptions include fresh unripened cheese which is chilled, like cottage and cream cheeses. When cheese is used in cooking, the dish should not be brought to boiling temperatures on the stovetop, and is generally added at the end stages of the cooking process, as in the case of sauces. While cheese is best served at room temperature, cheese used for cooking is easier to grate or shred when cold, like Cheddar and Swiss cheeses.
Cow milk is the most commonly used in cheese making. However, sheep milk, goat milk and buffalo milk cheeses are also very popular. Each type of milk differs slightly in its fat content and overall composition, and thus each imparts a distinctive flavour. Vegan cheese are also starting to appear and are often made with Cashews or soy proteins.