There are many different types of cheese, which can be grouped or classified according to criteria such as: length of fermentation, texture, production method, fat content, animal source of the milk, and country or region of origin.
[3][4] The combination of types produces around 51 different varieties recognized by the International Dairy Federation,[3] over 400 identified by Walter and Hargrove, over 500 by Burkhalter, and over 1,000 by Sandine and Elliker.
[5] Some attempts have been made to rationalise the classification of cheese; a scheme was proposed by Pieter Walstra that uses the primary and secondary starter combined with moisture content, and Walter and Hargrove suggested classifying by production methods.
[11] Other factors than moisture have a role in the firmness of the cheese; a higher fat content tends to result in a softer cheese, as fat interferes with the protein network that provides structure, other significant factors include PH level and salt content.
Colby and Monterey Jack are similar but milder cheeses; their curd is rinsed before it is pressed, washing away some acidity and calcium.
[19] Hard cheeses are packed tightly into forms (usually wheels) and aged for months or years until their moisture content is significantly less than half of their weight, leading to a firm and granular texture.
[26] Soft-ripened cheeses begin firm and rather chalky in texture, but are aged from the exterior inwards by exposing them to mold.
The mold may be a velvety bloom of P. camemberti that forms a flexible white crust and contributes to the smooth, runny, or gooey textures and more intense flavours of these aged cheeses.
[26] Washed-rind cheeses are soft in character and ripen inwards like those with white molds; however, they are treated differently.
Washed-rind cheeses are periodically cured in a solution of saltwater brine or mold-bearing agents that may include beer, wine, brandy and spices, making their surfaces amenable to a class of bacteria (Brevibacterium linens, the reddish-orange smear bacteria) that impart pungent odors and distinctive flavours and produce a firm, flavourful rind around the cheese.
Corsican brocciu, Italian ricotta, Romanian urda, Greek mizithra, Croatian skuta, Cypriot anari cheese, Himalayan chhurpi and Norwegian Brunost are examples.
Fresh curds are stretched and kneaded in hot water to form a ball of mozzarella, which in southern Italy is usually eaten within a few hours of being made.
They are classified as "cooked", meaning made using thermophilic lactic fermentation starters, incubating the curd with a period at a high temperature of 45°C or more.
Traditionally the cheeses were made in large rounds or "wheels" with a hard rind, and were robust enough for both keeping and transporting.
[49] The best known cheeses of the type, all made from cow's milk, include the Swiss Emmental, Gruyère and Appenzeller, as well as the French Beaufort and Comté (from the Jura Mountains, near the Alps).
Both countries have many other traditional varieties, as do the Alpine regions of Austria (Alpkäse) and Italy (Asiago), though these have not achieved the same degree of intercontinental fame.
[50] Most global modern production is industrial, and usually made in rectangular blocks, and by wrapping in plastic no rind is allowed to form.
[51] The general eating characteristics of the Alpine cheeses are a firm but still elastic texture, flavor that is not sharp, acidic or salty, but rather nutty and buttery.
They seem to have borrowed their techniques from them, but produced very different cheeses, using much more salt, and less heating, which suited the local availability of materials.
This process gives the cheese good stability, inhibiting bacterial growth even in hot environments.
[54] Brined cheeses may be soft or hard, varying in moisture content, and in color and flavor, according to the type of milk used.
All will be rindless, and generally taste clean, salty and acidic when fresh, developing some piquancy when aged, and most will be white.