(Avena sativa L.) is a cereal crop. Oats is widespread in the temperate zones of the world, where it is typically grown in the more humid areas and more acidic soils. It has long been a major crop in Scotland and the Scandinavian countries. Oats has traditionally been used for feeding horses and other livestock and for human consumption in porridges, flat breads, or cookies. After de-husking the oat goes through a steaming process that gelatinizes the starch. It can then be either milled to make oatmeal or flaked to make traditional oat flakes. In beer brewing, especially for stouts, oats has been used as flakes and in malted form. See oatmeal stout. Toasted “golden” oat flakes are also now available to brewers. Oats add their own distinct flavor and a notably oily, round mouthfeel. While oat hulls may be used like rice husks to ease lautering in certain beers, oats themselves contain beta-glucans and other gummy substances that tend to clog the mash and impede run-off. Oats may also give cloudy worts and cause strong foaming during fermentation. Hence, most brewers prefer to keep the oat fraction of the grist under 10%, though the adventurous few will push the fraction higher in order to attain qualities they consider desirable.