Staining of Barley Kernels by Bacteria

The demand for beer light in color has placed emphasis on the need to regulate malting as to produce, naturally and consistently, malts that are light in color (Bawden and Artis 1954), and malt having a clean pleasing aroma (Hopkins and Krause 1937). Even when bright barley, relatively free of field fungi, is malted, the finished product tends to be darker in color than the starting materials; in some cases to the extent that bleaching with sulfur dioxide gas is required (Hopkins and Krause 1937; Oesting et al. 1949). The cause of this discoloration is not known, but bacteria might conceivably be involved, since large numbers of bacteria have been found in most barley samples examined (Follstad 1961; Pepper 1960)