wheat, any of several species of cereal grasses of the genus Triticum (family Poaceae) and their edible grains. Wheat is one of the oldest and most important of the cereal crops. Of the thousands of varieties known, the most important are common wheat (Triticum aestivum), used to make bread; durum wheat (T. durum), used in making pasta (alimentary pastes) such as spaghetti and macaroni; and club wheat (T. compactum), a softer type, used for cake, crackers, cookies, pastries, and flours. Additionally, some wheat is used by industry for the production of starch, paste, malt, dextrose, gluten, alcohol, and other products.
Most wheat used for food requires processing. The grain is cleaned and then conditioned by the addition of water so that the kernel breaks up properly. In milling, the grain is cracked and then passed through a series of rollers. As the smaller particles are sifted out, the coarser particles pass to other rollers for further reduction. About 72 percent of the milled grain is recovered as white flour. Flour made from the whole kernel is called graham flour and becomes rancid with prolonged storage because of the germ-oil content retained. White flour, which does not contain the germ, preserves longer. Inferior and surplus wheats and various milling by-products are used for livestock feeds.
