Flour is a powder which is made by grinding cereal grains, or other seeds or roots (like Cassava). It is the main
ingredient of bread, which is a staple food for many cultures, making the availability of adequate supplies of flour a major economic and political issue at various times throughout history. Wheat flour is one of the most important foods in European, North American, Middle Eastern, Indian and North African cultures, and is the defining ingredient in most of their styles of breads and pastries.
While wheat is the most common base for flour, maize flour has been important in Mesoamerican cuisine since ancient times, and remains a staple throughout the Americas. Rye flour is an important constituent of bread in much of central Europe, and rice can also be used in flour, though this is relatively uncommon.
History[]
It was discovered around 6000 BC that wheat seeds could be crushed between simple millstones to make flour. The Romans were the first to grind seeds on cone mills. In 1879, at the beginning of the Industrial Era, the first steam mill was erected in London. In the 1930s, some flour began to be enriched with iron, niacin, thiamine and riboflavin. In the 1940s, mills started to enrich flour and folic acid was added to the list in the 1990s.
Degermed and heat-processed flour[]
An important problem of the industrial revolution was the preservation of flour. Transportation distances and a relatively slow distribution system collided with natural shelf life. The reason for the limited shelf life is the fatty acids of the germ, which react from the moment they are exposed to oxygen. This occurs when grain is milled; the fatty acids oxidize and flour starts to become rancid. Depending on climate and grain quality, this process takes six to nine months. In the late 19th century, this process was too short for an industrial production and distribution cycle. As vitamins, micro nutrients and amino acids were completely or relatively unknown in the late 19th century, removing the germ was a brilliant solution. Without the germ, flour cannot become rancid. Degermed flour became standard. Degermation started in densely populated areas and took approximately one generation to reach the countryside. Heat-processed flour is flour where the germ is first separated from the endosperm and bran, then processed with steam, dry heat or microwave and blended into flour again.
Production[]
Milling of flour is accomplished by grinding grain between stones or steel wheels. Today, "stone-ground" usually means that the grain has been ground in a mill in which a revolving stone wheel turns over a stationary stone wheel, vertically or horizontally with the grain in between. Many small appliance mills are available, both hand-cranked and electric. The mill stones frequently rub against each other resulting in small stone particles chipping off and getting into flour, but they are removed before the flour is sold.
Composition[]
Flour contains a high proportion of starches, which are a subset of complex carbohydrates also known as
polysaccharides. The kinds of flour used in cooking include all-purpose flour, self-rising flour (known as self-raising outside North America), and cake flour including bleached flour. The higher the protein content the harder and stronger the flour, and the more it will produce crusty or chewy breads. The lower the protein the softer the flour, which is better for cakes, cookies, and pie crusts.
Unbleached flour[]
Unbleached flour is simply flour that has not undergone bleaching and therefore does not have the color of "white" flour. An example of this would be the Graham flour. Sylvester Graham was against using bleaching agents, which he considered unhealthy.
Bleached flour[]
Bleached flour is artificially aged using a bleaching agent, a maturing agent, or both. A bleaching agent would affect only the carotenoids in the flour; a maturing agent affects gluten development. A maturing agent may either strengthen or weaken gluten development.
Plain flour[]
Flour that does not have a leavening agent is called plain or all-purpose flour. It is appropriate for most bread and pizza bases. Some cookies are also prepared using this type of flour. Bread flour is high in gluten protein, with 12.5-14% protein compared to 10-12% protein in all-purpose flour. The increased protein binds to the flour to entrap carbon dioxide released by the yeast fermentation process, resulting in a stronger rise.
Types of flour[]
Wheat flour[]
More wheat flour is produced than any other flour. Wheat varieties are called "clean," "white," or "brown" or "strong" or "hard" if they have high gluten content, and they are called "soft" or "weak" flour if gluten content is low.
acorn flour
Acorn flour[]
Acorn flour is made from ground acorns and can be used as a substitute for wheat flour. It was used by Native Americans. Koreans also use acorn flour to make Dotorimuk.
Cassava flour[]
Cassava flour is made from the root of the cassava plant.
Coconut flour[]
Coconut flour is made from ground coconut meat and has the highest fiber content of any flour, having a very low concentration of digestible carbohydrates makes an excellent choice for those looking to restrict their carbohydrate intake.
Hemp flour[]
Hemp flour is produced by pressing the oil from the hemp seed, and milling the residue. Hemp seed is approximately 30% oil and 70% residue. Hemp flour doesn't rise, and is best mixed with other flours. Added to any flour by about 15-20%, it gives a spongy nutty texture and flavor with a green hue.
Noodle flour[]
Noodle flour is a special blend of flour used for the making of Asian style noodles. The flour could be from wheat or rice.
Enriched flour[]
Main article: Enriched flour
Products made from Flour[]
Bread, pasta, crackers, many cakes, and many other foods are made using flour. Wheat flour is also used to make a roux as a base for thickening gravy and sauces. It is also the base for papier-mâché. Cornstarch is a principal ingredient used to thicken many puddings or desserts, and is the main ingredient in packaged custard.
