Relationships of sweetness in lager to selected volatile congeners

Abstract

Lager is generally brewed to minimise the final sugar content but despite this can have sweet characters. Such flavour notes have been ascribed to concentrations above flavour thresholds of certain volatile congeners: maltol; 4-hydroxy-2,5-dimethyl-3(2W)furanone (HDMF); 4-hydroxy-2(5)-ethyl-5(2)-methyl- 3(2#)furanone (HEMF); hydroxymethylfurfural (HMF); diacetyl; and specific esters (ethyl acetate, ethyl caproate, ethyl caprylate, and iso amyl acetate). Relationships between scoring of sweetness in lagers and quantitative data on relevant congeners and ethanol were explored. Lagers (23) were scored for sweetness using rank rating and in 18 lagers ten relevant volatile congeners were quantified by gas chromatography. Relationships between sensory and compositional data were modelled. Multiple linear regression was less successful than partial least squares regression (PLS1) based on four principal factors. Calibration values for r2 were 0.70 and 0.77, when ester data was excluded and included, and validation values were 0.56 and 0.45, respectively. Prediction was improved to a validation r2 = 0.74 when an artificial neural network was used in modelling with the complete compositional data set. It was concluded that in lagers a range of congeners and ethanol contribute in a complex manner to perceptions of sweetness and the relationship with 4-hydroxyfuranone derivatives merits revaluation. © 2004 The Institute & Guild of Brewing.