Thirty-seven lines from a population derived from the hull-less barley cultivar, Penthouse, were grown in a replicated trial over three seasons and assessed for grain yield. Following harvest, a rapid test to measure grain dimensions was applied to all samples, to look for novel variation in grain size and shape, as a possible way of detecting mutations. A range of grain and malt quality traits was also measured in two of the seasons, to detect genotype × season interactions and determine relationships between the measured traits. There were significant differences between years for all traits and between genotypes for most. Genotype × season interaction was significant for grain dimensions and some malting traits, but a correlation between malting quality and grain dimensions was only observed in one season. Line 30 showed very high yield potential in a comparatively wet season and gave a higher alcohol yield per unit area than a hulled control variety, while lines 21 and 33 contained putative additional mutations. Line 21, previously observed to have higher enzyme activity, appeared to contain an additional dwarfing gene and was characterized by smaller grain, later ear emergence and lower yield. Line 33, with malting potential, showed considerably altered grain length to width ratio and will be further investigated as a possible globosum type.