Butter is a dairy product made from the fat and protein components of churned cream. It is a semi-solid emulsion at room temperature, consisting of approximately 80% butterfat. It is used at room temperature as a spread, melted as a condiment, and used as a fat in baking, sauce-making, pan frying, and other cooking procedures.
Most frequently made from cow's milk, butter can also be manufactured from the milk of other mammals, including sheep, goats, buffalo, and yaks. It is made by churning milk or cream to separate the fat globules from the buttermilk. Salt has been added to butter since antiquity to help preserve it, particularly when being transported; salt may still play a preservation role but is less important today as the entire supply chain is usually refrigerated. In modern times, salt may be added for taste. Food coloring is sometimes added to butter. Rendering butter, removing the water and milk solids, produces clarified butter, or ghee, which is almost entirely butterfat.
Butter is a water-in-oil emulsion resulting from an inversion of the cream, where the milk proteins are the emulsifiers. Butter remains a firm solid when refrigerated but softens to a spreadable consistency at room temperature and melts to a thin liquid consistency at . The density of butter is . It generally has a pale yellow color but varies from deep yellow to nearly white. Its natural, unmodified color is dependent on the source animal's feed and genetics, but the commercial manufacturing process sometimes alters this with food colorings like annatto or carotene.
The word butter derives (via Germanic languages) from the Latin butyrum, which is the latinisation of the Greek βούτυρον (bouturon). This may be a compound of βοῦς (bous), "ox, cow" + τυρός (turos), "cheese", that is "cow-cheese". The word turos ("cheese") is attested in Mycenaean Greek. The latinized form is found in the name butyric acid, a compound found in rancid butter and other dairy products.
Churning (butter)
Unhomogenized milk and cream contain butterfat in microscopic globules.