Changes in Germination and Malting Quality During Storage of Barley

Abstract

To increase brewing yield and efficiency, malts with high extract values, high enzymic activities and good modification are essential. To produce malt that meets these requirements, the barley employed must have minimal post-harvest dormancy and be able to germinate vigorously. The aims of this study were to determine the extent to which some Australian barley varieties changed during post-harvest storage, how these changes influenced germination characteristics, enzyme production and malt quality, and, of the germination tests examined, which gave the best indication of a barley's malting potential. Four commercially grown barley samples were obtained, one from Tasmania and three from Victoria. Each sample was stored at room temperature for one year. At monthly intervals, samples were taken and placed at −18°C. The germinative energy (GE) and germinative index (GI) of these samples were measured. Samples were also micro-malted and the quality of the malt was assessed using standard EBC methodology. Storage at room temperature positively influenced the germination characteristics of all samples, with concomitant improvements in hydrolytic enzyme production during malting and in a number of malt quality parameters. It was found that, of the germination tests examined, the GI consistently correlated with enzyme activities during malting and with various malt quality parameters thus indicating that the GI is a good indicator of malting potential.