Malt is germinated cereal grains that have been dried in a process known as "malting". The grains are made to germinate by soaking in water, and are then halted from germinating further by drying with hot air. By malting grains, the enzymes required for modifying the grain's starches into sugars, including the monosaccharide glucose, the disaccharide maltose, the trisaccharide maltotriose, and higher sugars called maltodextrines are developed. It also develops other enzymes, such as proteases, which break down the proteins in the grain into forms that can be used by yeast. Depending on when the malting process is stopped one gets a preferred starch enzyme ratio and partly converted starch into fermentable sugars. Malt also contains small amounts of other sugars, such as sucrose and fructose, which are not products of starch modification but were already in the grain. Further conversion to fermentable sugars is achieved during the mashing process.

The mucosa-associated lymphoid tissue (MALT) (also called mucosa-associated lymphatic tissue) is a diffuse system of small concentrations of lymphoid tissue found in various mucosal sites of the body, such as the gastrointestinal tract, thyroid, breast, lung, salivary glands, eye, and skin. MALT is populated by lymphocytes such as T cells and B cells, as well as plasma cells and macrophages, each of which is well situated to encounter antigens passing through the mucosal epithelium. In the case of intestinal MALT, M cells are also present, which sample antigen from the lumen and deliver it to the lymphoid tissue.