Effect of batch-to-batch variation on the quality of laboratory and commercially malted Oxbridge barley

摘要

The malting performance of two different batches of Oxbridge barley was studied. The study showed that a single 24 h continuous laboratory steep was suitable for steeping the two batches of Oxbridge to provide good quality malt. Although each batch represented the same variety, and was of similar malting quality, they behaved differently in terms of friability scores, filtration rate and predicted spirit yield (PSY) by day 4 of the germination period. Worts prepared from the two malts gave different patterns of filtration rates, showing that each batch of Oxbridge modified at a different rate and in a different way, although they achieved similar final PSY results at the end of the malting period. The two batches of Oxbridge both malted rapidly, but behaved differently in terms of modification pattern, as revealed by the Rapid Visco-Analysis peak viscosities, as well visual germination results. The results of this study confirmed that, given the same malting conditions, batch 1 germinated more rapidly than batch 2, and supports the view that Oxbridge shows some inconsistency as a malting barley variety. The study further showed that the PSY result per se is not necessarily a good indicator of optimum modification of finished malted barley. This study showed that, while a particular barley variety, such as Oxbridge, may be associated with certain qualities and can produce good quality malt when a short steeping cycle is used, other factors are likely to cause batch-to-batch variations from the same barley variety. While the short steeping cycle was very successful in producing high-quality laboratory malt from Oxbridge, and results in a significant reduction of the quantity of water required for steeping, reduces malting time and also saves costs, there is evidence that there may be some additional variability associated with Oxbridge malting barley.