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What is malt ?

Malting is a process applied to cereal grains, in which the grains are made to germinate and then quickly dried before the plant develops.

The term malt refers to several products of the process:

• The grains to which this process has been applied, for example malted barley (used for the production of beer or whiskey)
• The sugar derived from such grains and heavy in maltose, such as baker's malt, see below.

Malt can also refer to specific products, such as malt beer (generally alcohol-free beer), malt whiskey (whisky made from 100 percent malted grain, and malt whisky from one distillery, rather than blended, is called single malt), malted milk (a product of milk with malt) or malt extract (a specific soft drink with malt from Scandinavia)

Malting grains develop enzymes that are required to degrade starch into sugar. The most common of these enzymes is amylase, but several other enzymes are present as well. Barley is the most common malt because of its high enzyme content. Other grains may be malted, although the resulting malt may not have sufficient enzymatic content to convert its own starch content fully and efficiently.

The starch is degraded into smaller fragments, called maltodextrins, and a disaccharide called maltose. Maltose is also known as malt sugar. The mixture of maltodextrins and maltose is sometimes referred to as bakers's malt.

A typical malting process is as follows:

The fresh raw grains are washed and soaked for a period of time to begin germination. A constant moisture is held to promote germination and growth of the acrospire (sprout). The acrospire is allowed to grow to a length equal to the grain, or a little less (this process takes about 4-6 days for barley).

The "green malt" is then kilned at 38°C to 49°C for about 24 hours and then at 60°C to 71°C, until the moisture content is less than 6%. This heating stops the germination process, but keeps the enzymes intact.

Darker brewing malts are sometimes kilned in different ways to promote different characteristics. The dark colour is mainly due to the formation of caramel in an additional heating step.