Northern Xinjiang is grazing country, and the Kazakh, Kyrgyz and Mongolian herders who work it live largely on their animals. Dairy is central to the diet, and the range of products you will be offered in a yurt, a roadside stand or a market stall is much wider than most visitors expect.
Yoghurt, ayran and kaimak
Plain yoghurt is thick, sour and served in a bowl, often with sugar on the side. Ayran is the drinkable version: yoghurt whisked with water and salt, cold and refreshing, and the standard accompaniment to a heavy meal. Kaimak is clotted cream, skimmed off boiled milk and served thick, usually spread on bread with sugar or honey. Suzma is a drained, salty yoghurt cheese, used as a spread or stirred into soups.
Kurt
Kurt, sometimes called kurt or dried cheese, is the most portable of the dairy products: salted yoghurt curds pressed into hard balls and dried in the sun until they are almost like stone. They are eaten by sucking or softening in tea, and they have a sharp, salty, faintly sour taste that takes a moment to get used to. Sold in bags in every market in the north, they are the local snack to carry on a long drive.
Milk tea
The tea is made with brick tea boiled hard, then mixed with fresh milk and salt and sometimes with a little butter. It is drunk from bowls, in quantity, and it is both a drink and a meal when there is nothing else. In Uyghur teahouses further south, the tea is usually served without milk and with sugar or dried fruit.
Practical notes
Dairy sold at roadside stands and inside yurt camps is made on the premises and is generally safe, but it is unpasteurised - anyone pregnant or with a compromised immune system should be cautious. Many of these products are made from mare's or ewe's milk as well as cow's. If you are invited into a yurt, accept the tea; it is the basic gesture of hospitality, and refusing it is read as a rejection. There is also fermented mare's milk, which is mildly alcoholic - ask before drinking if that matters to you.
