The numerous cheeses (often named for their place of origin) depend for their distinctive qualities on the kind and condition of the milk used, the processes of making, and the method and extent of curing. They may be divided into two classes, hard cheeses, which improve with age under suitable conditions, and soft cheeses, intended for immediate consumption. Very hard cheeses include Parmesan and Romano; among the hard cheeses are Cheddar, Edam, Emmental, Gouda, Gruyère, Provolone, and Swiss. The semisoft cheeses include brick, Gorgonzola, Limburger, Roquefort, Muenster, and Stilton; some of the soft cheeses are Brie, Camembert, cottage, Neufchâtel, and ricotta.
Microorganisms introduced, or permitted to develop, in cheese during the ripening process impart distinctive flavors and textures. Roquefort, Stilton, and Gorgonzola owe their bluish marbling to molds; Emmental and brick are ripened by bacteria that produce gas, which is entrapped in the curd and thus forms holes, a distinctive feature of what in the United States is known as Swiss-style cheese; Limburger attains a creamy consistency through bacteria-ripening. During the curing period the casein is broken down into a more digestible form by enzyme action. Cheese is valuable in the diet as a source of protein, fat, insoluble minerals (calcium, phosphorus, sulfur, and iron), and, when made from whole milk, vitamin A. Process cheese is a blend of young and ripened cheeses or of different varieties, ground, heated with water and up to 3% of emulsifying salts, and poured into molds, usually loaf-shaped. It is often homogenized and pasteurized. Certain cheeses, such as American Baby Swiss, have become popular because of heightened interest in healthful low-fat, low-salt foods. For the same reasons, goat cheeses such as Chèvre, Montrachet, and Bucheron, have grown in appeal to health food adherents and gourmets.