Malt quality as affected by various steep aeration regimes.

French, B.J. and McRuer, G.R.

Abstract
A 90 ton batch of barley (Hartington variety) was steeped in 8 stainless steel conical bottom tanks each of about 11 metric tons capacity. All tanks were fitted with multiple injection points situated on the cone to provide ring aeration. Through these points humidified compressed air at a temperature of 20 degrees C was passed. Water was allowed to overflow from the tanks continuously during immersion periods. To determine the effect of various aeration and steeping schedules on malting quality, 4 variations were investigated as follows: (1) no aeration during steeping, (2) continuous aeration during air rests but not during immersion, (3) continuous aeration during steeping but not during air rests and (4) continuous aeration both during steeping and air rests. Analyses of the resulting malts did not reveal any significant differences in malt quality. In an additional study, the effect of bed depth on malt quality was followed using cages suspended at various depths in the tanks under normal steeping schedules. Improved modification was found at increased depths with malts having lower fine/coarse grind extract differences, higher colours, higher nitrogen and lower viscosities in resulting worts. This increased modification is traced to increased immersion times rather than to other factors.
Keywords : aeration barley malt malting quality steeping