A solid fat made from churning the fat from milk or cream until it solidifies. It is a water-in-oil emulsion, comprised of over 80% milkfat, but also containing water in the form of tiny droplets, perhaps some milk solids-not-fat, with or without salt; the texture is a result of working/kneading during processing at appropriate temperatures, to establish fat crystalline network that results in desired smoothness (compare butter with melted and recrystallized butter); used as a spread, a cooking fat, or a baking ingredient. Unsalted butter is preferred over salted butter because it permits greater leeway in seasoning recipes to taste. Butter will keep, well wrapped, for 1 month in the refrigerator or for up to 6 months in the freezer. "
"Sweet cream butter
Lightly salted butter "Butter - Explore the History and Making of Butter.