THE COMPOSITION OF FINE PARTICLES WHICH AFFECT MASH FILTRATION

Abstract

The fine particulate material from various types of mash has been analysed. These particles which influence the rate of wort separation consist of aggregates of protein, hemicellulose (pentosan and β-glucan), small starch granules and lipid. All grists investigated yielded such aggregates with similar qualitative composition but with marked variations in the relative amounts of individual components. There is no evidence that retrograded amylose contributes significantly to the composition of the aggregated particles. When heat stable β-glucanase is added to a mash containing 20% raw barley, neither the volume nor the β-glucan content of the fines changes appreciably but the texture is altered. The action of the glucanase loosens the structure of the particles to release small starch granules into the mash and the residual structure has a more porous appearance which probably allows freer passage of wort through the grain bed. The origin of mash-bed particles is the endosperm of the ungerminated barley or the under-modified regions of the malt.