Effect of germination conditions, with optimised steeping, on sorghum malt quality - With particular reference to free amino nitrogen

Using optimised steeping conditions for sorghum. the effect of various germination parameters (time, temperature and moisture) on the quality of sorghum malt for brewing purposes (in terms of diastatic power, free amino nitrogen and hot water extract) and on the associated malting losses, was investigated. Over the range studied (2, 4 and 6 days), the quality of the malt and the losses incurred during malting increased with increasing germination time. In general, the optimum germination temperature was between 25 and 30 degrees C. and 18 degrees C was found to be sub-optimal for the development of malt diastatic power. The quality of the finished malt and the associated malting losses were significantly correlated with the moisture content of the green malt. The root and shoot portion of the malt was found to be rich in free amino nitrogen (more than four times richer than the berry portion). Although a relatively small proportion of the total weight of the whole malt. the roots end shoots were found to contribute a substantial amount (as much as 61% under certain circumstances) to the whole-malt free amino nitrogen.