Cheese is a solid food made from the curdled milk of cows, goats, sheep, or other mammals. The milk is curdled using some combination of rennet (or rennet substitutes) and acidification. Bacteria acidify the milk and play a role in defining the texture and flavor of most cheeses. Some cheeses also feature molds, either on the outer rind or throughout.

There are hundreds of types of cheese. Different styles and flavors of cheese are the result of using different species of bacteria and molds, different levels of milk fat, variations in length of aging, differing processing treatments (cheddaring, pulling, brining, mold wash) and different breeds of cows, sheep, or other mammals. Other factors include animal diet and the addition of flavoring agents such as herbs, spices, or wood smoke. Whether or not the milk is pasteurized may also affect the flavor.

For a few cheeses, the milk is curdled by adding acids such as vinegar or lemon juice. Most cheeses, however, are acidified to a lesser degree by bacteria, which turn milk sugars into lactic acid, followed by the addition of rennet to complete the curdling. Rennet is an enzyme traditionally obtained from the stomach lining of young cattle, but now also laboratory produced. Substitute "vegetable rennets" have been extracted from various species of the Cynara thistle family.

In some societies, stored cheese is a hedge against famine and a good travel food. It is valuable for its portability, long life, and high content of fat, protein, calcium, and phosphorus. Cheese is lighter-weight, more compact, and has a longer shelf life than the milk from which it is made. Cheesemakers can place themselves near the center of a dairy region and benefit from fresher milk, lower milk prices, and lower shipping costs. Cheese's substantial storage life lets a cheesemaker sell when prices are high or money is needed. Some markets even pay more for "aged" cheeses, exactly the opposite case from conventional milk production.

Cheeses are eaten raw or cooked, alone or with other ingredients. As they are heated, most cheeses melt and brown. Some cheeses, like raclette, melt smoothly; many others can be coaxed into doing so in the presence of acids or starch. Fondue, with wine providing the acidity, is a good example of a smoothly-melted cheese dish. Other cheeses turn elastic and stringy when they melt, a quality that can be enjoyed in dishes like pizza and Welsh rarebit. Some cheeses melt unevenly, their fats separating as they heat, while a few acid-curdled cheeses, including halloumi, paneer and ricotta, do not melt at all and can become firmer when cooked.



Origins
The exact origins of cheesemaking are unknown, and estimates range from around 8000 BCE (when sheep were domesticated) to around 3000 BCE. Credit for the discovery most likely goes to nomadic Turkic tribes in Central Asia, around the same time that they developed yogurt, or to people in the Middle East. A common tale about the discovery of cheese tells of an Arab nomad carrying milk across the desert in a container made from an animal's stomach, only to discover the milk had been separated into curd and whey by the rennet from the stomach.

Folktales aside, cheese likely began as a way of preserving soured and curdled milk through pressing and salting, with rennet introduced later— perhaps when someone noticed that cheese made in an animal stomach produced more solid and better-textured curds. The earliest archaeological evidence of cheesemaking has been found in Egyptian tomb murals, dating to about 2300 BCE. The earliest cheeses would likely have been quite sour and salty, similar in texture to rustic cottage cheese or feta.

From the Middle East, basic cheesemaking found its way into Europe, where cooler climates meant less aggressive salting was needed for preservation. With moderate salt and acidity, the cheese became a suitable environment for a variety of beneficial microbes and molds, which are what give aged cheeses their pronounced and interesting flavors.

J'ADORE FROMAGE!