Koumiss is a fermented milk drink.
It is mostly made from cow’s milk, though it was originally made from horse’s milk, and some stables in Russia still produce it as a side-business.
The starter used is a combination of fungus and yeast. Koumiss from a previous batch can be used as a starter, if it is unpasteurized.
While the milk is fermenting, it needs to be shaken frequently to keep the product homogenized and so stop it from settling.
It has a tart taste, and an alcohol content of 1 to 2 %. It was traditionally seen as being good for your stomach.
Arag can be made from Koumiss.
On average, 2% fat, 2% protein, 2% lactose
Koumiss used to have limited shelf life of only 3 days before a process was developed to pasteurize it.
May have originated with the Mongols.