The impact of malt blending on lautering efficiency, extract yield, and wort fermentability

The impact of malt blending on brewing performance in terms of extract, lautering, and fermentability performance was examined in a series of small-scale mashing trials. Malts were blended so that 40–60% of the grist consisted of malt with lower levels of one or more of these malt quality characteristics. With extract, blending resulted in additive improvements between malts of lower and higher levels. In contrast, improvements were synergistic for lautering performance when there was a substantial difference between the lautering performance of the two malts. The markers for synergism in lautering performance were the level of â-glucanase and wort viscosity. Fermentability performance also typically showed synergism between low and high fermentability malts, with the exception of one malt sample whose blend combination showed an unexplained antagonism. The synergism in fermentability performance was achieved when there was a deficiency between the malts for Kolbach index, the diastatic power enzymes, or â-amylase thermostability that compensated for the lack of these components in the lower-fermentability malts. The importance of these blending interactions was discussed in relation to malt quality specifications and achieving consistent and predictable brewing outcomes.