The age-old technique has remained unchanged: A curdling agent is used to coagulate milk, for example rennet, a natural ingredient extracted from calves' stomachs. Certain plants can also be used to coagulate milk, for example Yellow Bedstraw (Galium verum), artichoke or thistle. The curds obtained are sometimes heated then salted, strained, placed in moulds or even pressed to be eaten fresh or left to dry and mature for a variable length of time, depending on local traditions.
Dairy processing techniques are thought to have originated in Central Asia with the emergence of livestock farming. Today, in Mongolia, curdled yak’s, sheep’s and goat’s milk is called biaslak. It is eaten fresh the very same evening or cut into slices and hung up to dry on a thread so that it will keep for several months. In Uzbekistan, chaka, strained yoghurt, is used to make kurut, small balls that are left to dry in the sun for a number of weeks, eaten as snacks or crumbled over dishes. They are so valuable that they are sometimes used as currency.
In Europe, until the Middle Ages, people used to eat a lot of fresh, dried or smoked cheese. Later, over the course of the centuries, monks refined maturing techniques. Cooked cheeses were thus born, for example Gruyère and Emmental in Switzerland, creating a vibrant local economy in the mountain pasture regions.