About Butter
Butter is made from the cream of milk, with 10 cups (2.5 quarts) of milk required to generate one stick (1/4 pound) of butter. Butter contains about 80 percent milk fat, no more than 16 percent water, and 4 percent milk solids. Salt and coloring additives such as extract of annatto seed or carotene may or may not be added.
As cream converts to butter, dramatic changes occur, because milk is an oil-in-water emulsion, which reverses to a water-in-oil emulsion in butter. Methods of making butter start with cooled cream, which is stirred or, in commercial operations, centrifuged to expel water from the cream. The mechanical agitation breaks the phospholipid membranes around the fat globules, causing the milk fat to escape and lump together. This causes the fatty portion to separate out as a soft, yellowish solid; these are granules of butter the size of corn kernels. Liquid drained from the process is collected and called buttermilk, a tangy tasting, opaque, reduced-fat milk by-product. The butter granules are washed and then churned at slower speed until they are mixed into a smooth, homogenous paste. Any remaining water is drained, and salt is sometimes added at this point for flavor and to act as a preservative. In commercial dairies, the process is begun with a cream that is concentrated up to 80 per-cent fat, and then further concentrated to 98 percent. It is first pasteurized to destroy pathogenic bacteria, cooled, and then recombined with the milk solids and water.
Once it is formed, commercial butter is divided into blocks that are individually wrapped, usually in waxed paper, to prevent odor absorption from other foods. Butter bought at the market has usually been cut into quarter-pound segments and rewrapped, and is sold in wrapped or boxed half-pound or one-pound packages. Grading is voluntary on the part of the processor and is based on the butter’s texture, flavor, color, and salt content.
Butter can be purchased in a number of forms. Taste options are sweet cream butter, with or without added salt, and cultured butter, which has been acidified by lactic bacteria. A popular variant in texture is whipped butter, which is lighter in weight than regular butter and easier to spread because it has been aerated with air or nitrogen gas. Its lower density results in butter with half the calories (kcal) - 50 rather than 100 calories (kcal) per tablespoon - of regular butter on a solid volume, unmelted basis. More of the whipped than the regular butter may be needed, however, to get the equivalent flavor and color. Another type of butter, called compound, composed, or flavored butter, is a softened butter mixed with one or more flavors, such as garlic, lemon, honey, wine, herbs, or nuts.
One of the newer forms, powdered butter, is made by removing the fats in natural butter and chemically treating, drying, and combining it with various ingredients - whey solids, maltodextrins, guar gum, corn syrup solids, and color additives. Powdered butter can be reconstituted with hot water and used in food service establishments to add flavor to vegetables, sauces, soups, and baked products. It is lower in calories (kcal) and cholesterol than natural butter.
Regular butter, or whole butter, must be specially treated before it can be used in certain types of food preparation involving high heats, because its milk solids burn very easily. Butter so treated, called clarified butter (ghee in Indian cuisine), is almost 100 percent fat. It is easily obtained by melting butter over low heat, allowing it to cool until the heavier, cloudy-looking milk solids have settled out, and gently pouring off the clear liquid portion. The smoke point of clarified butter is much higher than regular butter.
Sometimes regular butter is preferred, because the tendency of its milk solids to burn can also have a positive effect in food preparation. It allows the nuttier-flavored brown butter, or Beurre Noisette, and black butter, Beurre Moir, to be made by heating butter over low heat until it turns the desired color.
