Skim milk is a dairy product with an extremely low fat percentage. In some nations, skim milk is labeled as “fat free” milk, since many labeling laws allow foods with negligible fat contents to be labeled as “fat free”. Most grocery stores and dairies stock skim milk, along with low-fat and whole milk products. For people who are concerned about the amount of fat in their diets, skim milk is an excellent alternative to whole milk, although some individuals do not enjoy the flavor.
Traditionally, dairy was allowed to sit after milking, to allow the fat to rise to the top. The fat was skimmed to make butter and cream products, and the remaining milk was consumed or processed into other foods like cheese. Modern dairy production uses centrifuges, since they are much more time efficient. After being centrifuged, the fatty part is used to make cream and butter, or it may be added back into the skimmed milk to raise the fat percentage.
As a general rule, products labeled as “skim milk” have less than 0.5% fat. Low fat or semi-skimmed milk has a fat percentage ranging between one and two percent. Many dairies label their one and two percent milk separately, giving consumers more options. Whole milk has a fat content of around 3.5%. Creams and butters, made from the fatty part of the milk, have a much higher fat content. A dairy may also choose to supplement its dairy products with useful vitamins and minerals such as calcium and vitamin D.
Most dairies pasteurize their milk products out of concern for safety. After separation into skim milk, whole milk, and other dairy products, the milk is also usually homogenized. Homogenization evens the consistency of the milk by reducing all of the particles in the milk to the same size. This prevents fatty solids from rising to the top of the milk as it sits. Because most milk is homogenized, making skim milk at home is essentially impossible, unless you have access to milk which has not been so treated.
As a general rule, skim milk will keep under refrigeration for five to 10 days. Always check the expiration date on milk and dairy products when you purchase them, and sniff dairy products when you open them to ensure that the contents have not spoiled. Skim milk can be used as a milk alternative in a wide range of foods, although the lower fat content may make it unsuitable for certain cooked dishes. Skim milk also tends to have a slightly watery flavor, which some consumers do not enjoy.