A Dairy Product
Fresh milk, if left to sit undisturbed, will separate: to the top will rise a layer of thick rich cream full of milk or butter fat, floating over a much larger mass of fat-free skim milk. If left long enough the cream will get so thick it must be spooned off. Once removed, and if left even longer in its natural state, the friendly bacteria it contains turn it into a slightly fermented but delicious product such as crème fraîche or sour cream. These days, however, cream is usually summarily separated from milk by centrifugal force in giant whirling machines, after which it is pasteurized before commercial sale, killing those bacteria and making the natural evolution to naturally thickened creams impossible.
This is sad.
Commercial cream is sold under several labels, differentiated according to the amount of milk fat it contains. Here they are, from lightest/least fat to heaviest/most fat:
- Half and half is a mixture of milk and cream and contains 10-12% fat.
- Light, coffee or table cream may contain 18-30% fat, but around 20% is most common.
- Whipping cream generally contains 30-36% fat and often also contains stabilizers and emulsifiers; sneff mentions something which sounds very similar in Australia sold as thickened cream, which may contain gelatine, so vegetarians beware. ("Real" whipped cream in pressurized cans isn't really whipped at all, though it is real cream; it's expanded by gas - usually nitrous oxide - into a puffy form, and besides cream contains sugar, stabilizers, and emulsifiers. Aerosol "dessert toppings" like Dream Whip aren't really very dreamy when you consider that they're made from hydrogenated vegetable oil; give those a miss and get the real thing.)
- Heavy cream is even fattier than whipping cream, with between 36 and 40% fat, but it can be hard to come by except in gourmet stores.
- Double or "real" cream, at 45%+ fat, is thick and rich - spoonable, like clotted cream.
A Culinary Technique
Recipes for cake and the like often advise the cook to cream ingredients such as butter and sugar together. This means you have to beat the ingredients or combination of ingredients together until smooth, soft, and creamy. Ideally, the end result should be homogeneous, showing neither separation of liquid from fat nor evidence of crystals such as sugar. If it's butter you're creaming, make sure it's at room temperature before you begin, and pay attention to the suggested timing in the recipe, if any; overbeating can produce disastrous curdled results. If at all possible, use an electric mixer or food processor for creaming; a fork can take a long time and a lot of elbow grease to give the same results.