Source: CD Kitchen
Originally, buttermilk was the liquid left over from churning butter from cultured or fermented cream. Traditionally, before cream could be skimmed from whole milk, the milk was left to sit for a period of time to allow the cream and milk to separate. During this time, naturally occurring lactic acid-producing bacteria in the milk fermented it. This facilitates the butter churning process, since fat from cream with a lower pH coalesces more readily than that of fresh cream. The acidic environment also helps prevent potentially harmful microorganisms from growing, increasing shelf-life.
Commercially available cultured buttermilk is milk that has been pasteurized and homogenized (if 1% or 2% fat), and then inoculated with a culture of lactic acid bacteria to simulate the naturally occurring bacteria in the old-fashioned product. Some dairies add colored flecks of butter to cultured buttermilk to simulate residual flecks of butter that can be left over from the churning process of traditional buttermilk.
Like powdered milk, buttermilk is available in a dried powder form. This stores well at room temperature and is usually used in baked goods.
Recipes using Buttermilk
>Nonfat dry milk and skimmed milk powder are very similar. Both are obtained by removing water from pasteurized skim milk. Both contain 5% or less moisture (by weight) and 1.5% or less milkfat (by weight). The difference is that skimmed milk powder has a minimum milk protein content of 34%, whereas nonfat dry milk has no standardized protein level.
Nonfat dry milk and skimmed milk powder are classified for use as ingredients according to the heat treatment used in their manufacture. There are three main classifications: high-heat (least soluble), medium-heat, and low-heat (most soluble).
Nonfat dry milk and skimmed milk powders are available in roller-dried and spray-dried form, the latter being the most common. Spray-dried nonfat dry milk and skimmed milk powders are available in two forms: ordinary or non-agglomerated (non-instant) and agglomerated (instant).
Ship and store in a cool, dry environment at temperatures less than 27°C and relative humidity less than 65%. The shelf life of non-instant nonfat dry milk powder is 12-18 months; instant is 6-12 months. Note that storage life is very dependent on storage conditions, and that this figure is only a guide. Under ideal conditions, non-instant nonfat dry milk powder can retain its physical and functional properties for at least two years; however, quality will be impaired if temperatures and humidity are too high and storage is extended.
Condensed milk is cow’s milk from which water has been removed. It is most often found in the form of sweetened condensed milk, with sugar added, and the two terms ‘condensed milk’ and ‘sweetened condensed milk’ are often used synonymously in the English language today.
Sweetened condensed milk is a very thick, sweet product which when canned can last for years without refrigeration if unopened. Though there have been unsweetened condensed milk products, they spoiled far more easily and are uncommon today. Condensed milk is used in numerous dessert dishes in many countries.
Condensed milk can be made from evaporated milk by mixing one measure of evaporated milk with one and a quarter measures of sugar in a saucepan, then heating and stirring the mixture until the sugar is completely dissolved, then cooling. It can be made by simmering regular milk until it is reduced by 60%, then adding sugar.
Source: Martha Stewart