Malting is a process applied to cereal grains, in which the grains are made to germinate by soaking in water and are then quickly halted from germinating further by drying/heating with hot air. Malting is thus a combination of two processes; notably the sprouting process and the kiln-drying process. These latter terms are often preferred when referring to the field of brewing for batches of beer or other beverages as they provide more in-depth information.
The term malt refers to several products of the process: the grains to which this process has been applied, for example malted barley; the sugar, heavy in maltose, derived from such grains, such as the baker's malt used in cereals like Rice Krispies; or a product based on malted milk, similar to a malted milkshake (i.e., "malts").
Whisky or beer can also be called malt, as in Alfred Edward Housman's aphorism "malt does more than Milton can, to justify God's ways to Man."
Malted grain is used to make beer, whisky, malted shakes, and malt vinegar. Malting grains develops the enzymes that are required to modify the grain's starches into sugars, including monosaccharides (glucose, fructose, etc.) and disaccharides (sucrose, etc.). It also develops other enzymes, such as proteases which break down the proteins in the grain into forms which can be utilized by yeast. Barley is the most commonly malted grain in part because of its high diastatic power or enzyme content. Also very important is the retention of the grain's husk even after threshing, unlike the bare seeds of threshed wheat or rye. This protects the growing acrospire (developing plant embryo) from damage during malting, which can easily lead to mold growth. It also allows the mash of converted grain to create a filter bed during sparging (see brewing). Other grains may be malted, although the resulting malt may not have sufficient enzymatic content to convert its own starch content fully and efficiently and may create a "stuck sparge"