Changes in bitterness as beer ages naturally

Abstract In order to ascertain changes in bitterness as beer aged naturally, time–intensity (TI) measurements were made by a professional sensory panel using a squeezer transducer system. TI parameters were fitted by variance components models using Restricted Maximum Likelihood (REML). It was shown that bitterness decreased with age, although this age-induced difference was smaller than the original differences among the eight fresh (commercial lager) beer types which spanned about 10 European Bitterness Units (EBU). Intensity-related parameters obtained from the TI curves were more important than time-related parameters for differentiating samples. Perceived bitterness could not be explained entirely by concentrations of five iso-α-acid peaks as measured by High Performance Liquid Chromatography (HPLC). Analytical and sensory data were correlated using Partial Least Squares (PLS2) and by fitting iso-α-acid peak areas in the REML models. ©