The Evolution of Dextrins During the Mashing and Fermentation of All-malt Whisky Production

Abstract

The production of malt whisky involves the mashing of barley malt, followed by the fermentation of the resulting wort without further treatment. While this process has many parallels to the production of an all-malt beer, one of the main differentiating steps during substrate preparation is the inclusion of a boiling step for the wort in the production of beer. Other than the destructive action of the boiling process on microorganisms, the boiling also destroys all malt enzyme activity. Since a typical whisky wash is not boiled it carries through a certain proportion of microbial activity associated with the malt, but more importantly it retains some enzyme activity that has been activated during the malting and mashing processes. The changes in sugars and dextrins during both mashing and fermentation of the resulting wash were investigated. Evidence of the continuous amylolytic activity during an unboiled, all-malt wash fermentation is shown; while no ongoing amylolytic activity could be deduced during the fermentation of a boiled all-malt wort. Furthermore, the data suggests that the amylolytic activity during mashing and fermentation are different with regards to α-amylase action linked to its multiple-attack action pattern as a function of substrate conformation, temperature, and effectiveness of potential hydrolytic events.