Kumis is a fermented dairy brew traditionally made from mare's milk. Mare milk is a milk produced by female horses more than four years old. In Mongolia, Kazakhstan and Kyrgyzstan the mare milk is traditionaly fermented it in a horse-hide sack until it turns into a frothy, acrid and mildly alcoholic beverage named Kumis. Kumis normaly contains around 1% to 2.5% alcohol. But the finished product is often distilled to make Mongolian milk liqueur called Airag which contains 12% or Mongolian Vodka called Arkhi which contains 30% alcohol.