From The Modern Encyclopedia, published in the early 1930s:
Malt. Raw material of the brewer and distiller. It is produced by causing the seed grains of various cereals, principally barley, to germinate, whereby enzymes or ferments are secreted and developed, converting the albumen of the grains into diastase and the starch into sugar. When the growth has been stopped, the malt is screened to remove the rootlets, which contain about 43 per cent of digestible carbohydrates and albuminoids. Under the name of malt-culms or malt coombs these are given as a nourishing food to milk-cows and other cattle. Malting is the name given to the process of converting barley into malt.