The term malt can refer to several things but we’ll focus on the definitions that pertain to beer.
According to the German Purity Law, malted barley is one of the four primary ingredients of beer, the others being hops, yeast, and water. Once barley, or a number of other grains, has been malted, it is sometimes referred to simply as malt. The sugar that is extracted from malted grain can also be called malt.
When a grain is malted, is is soaked in water which starts the germination or sprouting process. The grain is allowed to germinate for several days then heated, or kilned, to stop the process. Without getting into the chemistry or biology of the process, malting modifies the grain so that the sugars can be more easily extracted from it.
The longer the grain is kilned, the darker it gets. Darker grains make darker beer. The malted grain can also give the beer different flavors depending on how long it is kilned.
Barley is the primary grain used to make beer but there are many varieties of barley used in brewing. Other grains are often used including wheat, rye, rice, and others. The grains can be divided into two groups: base grains and specialty grains.
- Base grains, which make up the majority grain used in a beer recipe, provide most of the fermentable sugars which are converted into alcohol during fermentaion.
- Specialty grains are used more sparingly and primarily contribute color and flavor to the beer.
By combining base grains and specialty grains, and choosing from the variety of hops and yeast available, the brewer is able to create a unique recipe.