Development and Use of a Method for Determination of Malt Fermentability

Abstract

A method for the determination of the fermentability of unboiled, filtered, malt Hot Water Extracts has been developed. The wort is fermented under carefully controlled conditions, using fresh dis tillers' yeast. Knowledge of a malt's extract and fermentability allows calculation of its fermentable extract content, which allows spirit yield prediction, and the method is in use as a basis for Malt Purchase Specifications.

Analysing the contribution of component cultivars and cultivar combinations to malting quality, yield and disease in complex mixtures

“…19 For HWE, 20 g of grist was extracted in 140 mL and made up to a final volume of 206 mL, while FERM was determined 48 h after addition of 0.5 g distillers' yeast to 100 mL of wort. The product of HWE and FERM is the fermentible extract 20 and this was converted to a predicted spirit yield (PSY) by means of an empirical factor employed by Scotch whisky distillers. 21 PSY is a measure of the amount of alcohol obtainable from a tonne of malt.…”

125thAnniversary Review: Barley research in relation to Scotch whisky production: a journey to new frontiers

“…Gray and Dewar reported the evaluation of a fermentability method based on residue gravity, which at that time was undergoing collaborative trials by distillers and maltsters. The fermentability method that was finally developed, gave values for both fermentable extract and predicted spirit (alcohol) yield (PSY) and was adopted as a standard Institute of Brewing Recommended method (Method 2.16). Over the years there have been minor changes to the fermentability method, principally with the change in the HWE procedure from 515 mL mash, to 450 g mash .…”

Letter to the Editor: Update on Knowledge Regarding Starch Structure and Degradation by Malt Enzymes (DP/DU and Limit Dextrinase)

“…This provides the basis of our understanding of the biochemistry underlying the standard fermentability method 7,10,11 , which is still one of the principal barley malt quality parameters, recognised by both distillers and sales maltsters for commercial trading purposes.…”