Ghee is made by simmering unsalted butter in a large pot until all water has boiled off and protein has settled to the bottom. The cooked and clarified butter is then spooned off to avoid disturbing the milk solids on the bottom of the pan. Unlike butter, ghee can be stored for extended periods without refrigeration, provided it is kept in an airtight container to prevent oxidation and remains moisture-free. Texture, colour, or taste of ghee depends on the source of the milk from which the butter was made and the extent of boiling. In India, ghee is usually made with water buffalo's milk as it tends to be whiter than cow's milk.