Prediction and variability in malt fermentability is a concern for breeders and brewers. The primary purpose of this study was to determine the variation in fermentability using two different laboratory mash methods. Another experiment was conducted to develop a relationship between malt/wort parameters and malt fermentability with addition of adjunct. The prediction of malt fermentability was achieved by using stepwise multiple linear regression analysis to evaluate which quality factors were able to best explain the observed variation in fermentability. The hot water extract (HWE) mash protocol showed a wider range of fermentability values than did the Congress mash. However, hot water extract mash method clearly showed better discriminative power. Diastatic Power (DP) explained about 50% of the variation in fermentability when using the Congress mash with all malt (i.e. 100%) and also with adjunct. While in case of HWE extract protocol, limit dextrinase activity was able to explain 32% of variation in fermentability with all malt and also with adjunct.