BARLEY MATURITY AND THE EFFECTS OF STEEP AERATION ON MALTING

Micromalting experiments were carried out with barleys varying in maturity. During steeping, which included water changes, the barleys were either allowed to remain static (the controls) or were mixed at intervals or were mixed continuously in continuously aerated water. No significant improvement in the uniformity of endosperm hydration, relative to controls, was found where grains had been mixed or were continuously aerated during steeping. Mature barley responded to continuous aeration with rapid germination during the steeping process, resulting in high malting losses. Periodic mixing during steeping had little effect on malt quality. It is suggested that, where air-rests are provided and mixing is not required to alleviate pressure, aeration (air-sparging) may be of no benefit when malting mature barley. Water-sensitivity was partially overcome by constant aeration, although periodic mixing was ineffective, hence aeration may be useful in malting water-sensitive barleys. The use of intermittent or continuous aeration inhibited the germination of undried dormant barleys. It is suggested that this effect was due to the excessive proliferation of microorganisms where aeration and mixing were provided.