malt, Grain product used in beverages and foods. Malt provides a basis for fermentation and adds flavour and nutrients. It is made by steeping grain, usually barley, in water and allowing partial germination to occur. The flavour of beer primarily results from the malt from which it is made. The enzymes produced within the barley seed during germination break down starch into malt sugar, or maltose, which is then fermented by yeast to yield alcohol and carbon dioxide. Whiskey likewise is made with malt.