MALT, the name given to grain in which germination has been caused to proceed to a certain stage and has then been arrested by the removal of water and the application of heat. During this limited germination enzymes are developed (see FERMENTATION), and the constituents of the modified so that the finished malt, when ground and submitted to the mashing process (see BREWING), differs from the original raw grain in that the greater portion dissolves. This solubility is due for the most part to the action of the malt enzymes, diastase, etc., on the constituents of the grain. Thus starch, the main constituent of all graminaceous seeds, probably exists in much the same condition in raw grain and in malt. When, however, the malt is mashed, the starch is at tacked by the enzyme diastase, and converted by the process of hydrolysis into a mixture of soluble compounds, e.g., the crystal line sugar, maltose, together with isomaltose and glucose and a number of gummy substances known as maltodextrins. It is now known that proteolytic enzymes exist in finished malt, and that, when the mashing process is conducted under certain conditions, these are able to degrade and render more permanently soluble some of the higher proteins present. By the limited germination which constitutes the malting process, the soluble compounds left in the finished malt is from 15 to 25% of total weight of the corn. Barley for Malt.—Barley belongs to the genus Hordeum, of which there are numerous species and varieties. Linnaeus and the earlier botanists recognized six species of cultivated barleys, but modern botanists usually consider all cultivated barleys as belong ing to one species to which the name H. sativum has been given. Kornicke regards H. spontaneum, a very long two rowed barley (see below) which grows in the East as the parent form; but E. S. Beaven inclines to the view that wild spe cies of more than one form were originally used as food and sub sequently cultivated.
Two-rowed barleys are favoured for malting purposes in Europe and are also grown to a certain extent on the Pacific coast of the United States.
Chevallier, a narrow-eared variety named for the original cul tivator Rev. John Chevallier, and a wide-eared selection from this variety called Goldthorpe are widely grown although they have been replaced largely by hybrids in recent years.
In America, the six-row barleys are favoured, the principal plantings being of hybrid varieties of the former Manchurian types.
Much was gained through Wahl's study of the Oderbrucker variety although very little is grown today.
O.A.C. 21, a blue strain of Manchurian developed by the On tario Agricultural college, and Wisconsin 38, a cross between Oderbrucker and a black smooth-awned barley, have been quite popular recently throughout the middle western sections of the United States and Canada.
In the common six-rowed English barley or Scottish bere the two lateral rows of spikelets springing from one side of the rachis either partially or entirely intersect and overlap the alternate lateral spikelets from the opposite side of the rachis. This has given rise to the term "four-rowed barley." Barleys were formerly developed through "selection" methods but cross-fertilization has enabled the agronomist to combine the good qualities of certain strains in such a manner that both are improved.