FACTORS AFFECTING WORT SEPARATION

Abstract

A laboratory mash filter is described which permits simple comparisons of the potential effects of different types of grist on wort separation. Particlesize has a major influence. Fine particles impeding flow can pre-exist in the grist, e.g. due to fine milling or use of flour adjuncts, or they can be formed by aggregation of macromolecules of glucans and pentosans with the protein coat of small starch granules, resulting in an impermeable matrix. Large starch granules, which have much less associated surface protein, do not form impervious aggregates in this way and do not impede wort run-off. Worts containing β-glucans show high viscosities when measured under standard conditions at 20°C. However viscosities are much lower at typical run-off temperatures. The deleterious effect of β-glucans on wort separation seems to be due only to a small extent to their effect on viscosity as such and is considered principally to be due to their participation as a component of the cementing material which causes fine particles to coalesce into impervious aggregates in the mash bed.