Butter is a concentrated source of milkfat (80%) with some water and nonfat milk solids. It is made from milk, cream or both of these ingredients. Common salt may or may not be added.
Traditional butter (80% milkfat) is made from pasteurized cream under approved conditions. The U.S. government grades butter on the basis of its flavor, body, color and salt content. The grades range from superior quality USDA Grade AA to standard quality Grade B. Most butter sold is USDA Grade AA. Grade B butter is used mainly for manufacturing purposes.
Salted butter contains 1.6-1.7% salt. This product is also sometimes called lightly salted butter. Salted butter can be stored refrigerated for up to 2 months. In the freezer, salted butter can be stored for 6-9 months.
Unsalted butter contains no added salt and is used in formulas where less salt is desired because of flavor or nutrition parameters. Unsalted butter can be stored for up to 2 weeks refrigerated and frozen for up to 5 months.
Whipped butter is regularly 80% salted or unsalted butter that has air or nitrogen gas whipped into it, resulting in a product with greater volume, reduced density and improved spreadability at colder temperatures.
Light butter typically contains skim milk, water and/or gelatin and is 40% (or less) milkfat. FDA regulations specify the ingredients and quantities that are acceptable in a light butter formulation. The regulation states that the product must not be nutritionally inferior to traditional butter and performance characteristics should be similar. Although light butter makes a fine spread or dressing, it should not be substituted for regular butter in baking or frying due to its high moisture content.
Cultured butter is made from pasteurized cream that has been inoculated with specific active lactic acid cultures, similar to those used in sour cream and buttermilk production. The reduction in pH and development of flavors produces a distinctive, pleasingly tangy flavored butter. Often times, cultured butter contains 82% milkfat and is used as a bakery fat. Cultured butter is common in Europe.
Anhydrous milkfat is made by removal of practically all of the moisture and nonfat solids from pasteurized cream. The 40% milkfat cream is first concentrated to 70-80% milkfat, and then the high-fat cream is processed through a specialized phase inversion unit or separator. The milkfat is further concentrated, with residual moisture removed by vacuum drying. Anhydrous milkfat contains no less than 99.8% milkfat and not more than 0.1% moisture.
Butteroil is made by the removal of practically all of the moisture and nonfat solids from butter. It is produced by gently heating butter, disrupting the butter emulsion. The milkfat is then concentrated in separators and vacuum dried to remove residual moisture. Sometimes butteroil is washed with water prior to the final drying stage to remove trace impurities. Butteroil contains about 99.5% milkfat and not more than 0.2% moisture.
Butter Powder delivers many of the same functional, sensory and texture attributes as butter. It is used in numerous applications where the use of butter is impractical or where the dry form offers some functional advantage to product developers. Manufacturing a butter powder involves adding nonfat milk solids to melted butter, homogenizing the mixture and spray drying. The resulting powder is free-flowing and microbiologically stable. Butter powder has a full strength, sweet cream butter flavor and is cream to light yellow in color. Source: American Butter Institute
Butter is a source of vitamin A. Its caloric content is about 100 calories per tablespoon, which compares to other spreads and fat ingredients.
Source: USDA Nutrient Database for Standard Reference.