PENTOSANS AND RELATED PRODUCTS IN MALTING AND BREWING

The number of references to pentosans and related substances in the brewing literature is out of all proportion to their potential influence on wort and beer. Published information shows that these substances appear to increase in amount in the grain during malting, whilst a proportion are rendered soluble and pass to the mash. Hop-boiling modifies the wort composition to some extent, whilst fermentation causes a notable loss of pentosans. A quantitative re-examination of the subject, using a Californian barley and its malt, and carried out as a preliminary to a projected more detailed study, confirms many of the points previously noted. Thus, malting gives a large increase in pento sans and, after mashing, some 12 to 20 per cent, of the malt furfuraldehyde can be recovered from the wort. Under the conditions employed, fermentation caused a loss of furfuraldehyde of the order of 30 to 40 per cent. Since the finished beer contains a high proportion of furfuraldehyde-yielding materials, it becomes of interest to consider the probable nature of these and their possible influence on beer properties.