Flour is a powder which is made by grinding cereal grains, seeds or roots. It is used as an ingredient for baking bread, cakes and in some other foods. Different cultures have flour made from different cereals and while in European, North America, Middle Eastern, Indian and North African cultures it is most commonly made from wheat, in Central America (Mesoamerica) it is made from corn from the ancient times while in central Europe it is made of rye. Some types of flour are made from rice.
Four is with us a long time now: there is archeological evidence that shows that flour was made some 30,000 years ago in the time of the Upper Paleolithic in Europe. Oldest technique for flour making was in combination of a stone mortar and pestle. The Romans made flour by grinding seeds on cone mills, combination of two stone of which one, upper, is convex and other, bottom, concave. Upper was turned by an animal while the bottom stood still. In time, different mechanisms of grinding of flour were invented. Ancient Greeks had watermills before 71 BC. Grain was fed between millstone, which was turned by the mechanism powered by water, and bedstone and grinded into powder. After watermills, appeared mills that were powered by wind. With the beginning of the Industrial age, mills were powered by steam and grinded the flour with rollers which were metal or porcelain, instead of horizontal stones. That increased flour production and gave a product with a longer shelf life. Before the industrialization, white flour was expensive and only affordable for the rich. Roller mills made removing of the germ much easier so white flour becomes more affordable for the poor. Problem is , that germ holds majority of the vitamin B an because white bread becomes staple food for the poor, diseases caused by lack of B vitamins such as pellagra and beriberi started appearing in large number. When the vitamins were discovered and their connection with diseases found during the 1930s, flour was enriched with iron, niacin, thiamine and riboflavin. Folic acid was added in the 1990s.
There are now different types of flour:
Unbleached flour is simply flour that has not undergone bleaching and therefore does not have the color of "white" flour.
Refined flour has had the germ and bran removed and is also called white flour.
Bleached flour is a type of refined flour that had added whitening agent. Four most commonly used agents are: potassium bromate, benzoyl peroxide, ascorbic acid and chlorine gas.
Plain flour or all-purpose flour is flour that does not have a leavening agent.
Self-rising flour is flour is sold premixed with chemical leavening agents. It is used for baking of lighter and softer baked products.
Enriched flour is a flour with replaced flour nutrients that are lost during processing.
Other flours that are made from other materials and that can be found on the market are: acorn flour, almond flour, amaranth flour, atta flour, bean flour, brown rice flour, buckwheat flour, cassava flour, chestnut flour, chickpea flour, coconut flour, corn (maize) flour, cornstarch, rice flour, hemp flour, maida flour, mesquite flour, nut flours, peasemeal or pea flour, peanut flour, potato flour, rice flour, rye flour, sorghum flour and tapioca flour.