Assessment of spirit yield in barley breeding lines

A number of random inbred lines of barley, grown at two sites, were assesse d for high gravity spirit yield. A range of values was obtained and there w as good agreement, for nearly all samples, between high gravity spirit yiel d and spirit yield predicted from extracts and fermentabilities measured by Institute of Brewing recommended methods. One sample, which gave a low pre dicted spirit yield but good high gravity spirit yield, was shown to have m odified poorly and unevenly. Over both sites, high gravity spirit yield app eared to correlate negatively with grain nitrogen content, but this reflect ed large differences between sites in grain nitrogen. High gravity spirit y ield did not correlate with soluble nitrogen, but did with fermentability, so samples with low levels of fermentability had either low or moderate lev els of high gravity spirit yield. It was concluded that identification of g enetic factors, influencing extract and fermentability, would enhance breed ing of barley cultivars suitable for malt whisky distilling.