Flour is always based on the presence of starches, which are complex carbohydrates.
Usually, the word "flour" used alone refers to wheat flour, which is one of the most important foods in European and American culture. Wheat flour is the main ingredient in most types of breads and pastries. Wheat is so widely used because of an important property: when wheat flour is mixed with water, a complex protein called gluten develops. The gluten development is what gives wheat dough an elastic structure that allows it to be worked in a variety of ways, and which allows the retention of gas bubbles in an intact structure, resulting in a sponge-like texture to the final product.
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2 Flour Production 3 History 4 Flour Products |
Wheat varieties are typically known as "hard" or "soft", depending on gluten content. Hard wheats are high in gluten, and soft wheats are low. Hard flour, or "bread" flour, is high in gluten and so forms a certain toughness which holds its shape well once baked. Soft flour is low in gluten and so results in a finer texture. Soft flour is usually divided into "cake" flour, which is the lowest in gluten, and "pastry" flour, which has slightly more gluten than cake flour.
In terms of the parts of the grain (the grass seed) used in flour -- the endosperm or starchy part, the germ or protein part, and the bran or fiber part -- there are three general types of flour. "White" flour is made from the endosperm only. "Whole grain" flour is made from the entire grain. A "germ" flour may also be made from the endosperm and germ, excluding the bran.
"Whole-wheat" flour is also referred to as "graham" flour in the USA, and is the basis of true graham crackers. Many of these crackers on the market are actually imitation grahams because they contain no whole-wheat flour.
In America, "white" corn (maize) flour is usually referred to as cornstarch. "Whole-grain" corn flour is usually referred to as corn meal. Corn meal which has been leached with lye is called masa harina and is used to make tortillas and tamales in Mexican cooking.
Flour can also be made from soy beans, arrowroot, potatoes, taro, and other non-grain foodstuffs.
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 water-operated mill, in which a revolving stone wheel turns over a stationary stone wheel, with the grain in between. Many small appliance mills are now available, both hand-cranked and electric.
Flour dust suspended in air is explosive, as is any mixture of a finely powdered flammable substance with air. Some of the worse civilan fatalities from explosions have been at flour mills.
In history, both large and hand mills were operated. Until modern times, flour contained minute amounts of fine sand, either the result of poor sifting of the grain or of grinding stones together. This sand strongly abraded teeth.
One of the most ancient methods of grinding corn was by using a hollowed-out rock (a quern), and the grain was placed in the hollow and pounded with another rock. This configuration was called a metate.
One of the great revolutions in human history came with the mechanical grinding of grains into flour, accomplished by the flour mill. The early mills were operated by animal power or water power.
Bread, pasta, many cakes, amongst many other foods, are made using flour.
Types of Flour
Flour Production
History
Flour Products