Many years ago, when there were no refrigerators, people had a difficult task: how to preserve and process milk, often a large amount, without a refrigerator.
During fasting or in summer, when there was surplus milk, it was poured into large earthenware jugs. Such dishes were made of very porous clay especially for milk. Then the jugs were placed in the cellar. After a while, the milk turned sour, and sour cream and yogurt formed in the jugs. Then, if these products could not be eaten, they were further processed. The sour cream was whipped and received butter, which could be stored for a long time - in the cold, in an earthenware dish filled with whey.
Butter was also melted and stored in this form in makitras - clay pots with a wide neck. Salt was often added to ghee. Such butter could be stored for several months, and if it was poured on top with melted pork fat, then even longer. Buttermilk, which was obtained along with butter, was given to livestock for feed. If buttermilk could be used for food, dough was kneaded on it, bread or pies were baked.
Curd was made from curdled milk, placing it under oppression. If the cottage cheese needed to be stored for a long time, the cottage cheese was "reheated" several times to make it as dry as possible, then eggs were added, baked until golden brown, tamped such cottage cheese in the form of pancakes in an earthenware dish, salted, and poured with melted butter. This made a cheese that could be stored for a long time and not spoil.
These methods made it possible to process even a large amount of milk, and preserve healthy and nutritious products for a long time.