Molecular insights into the contribution of oak barrel aging to the aroma of beer with high alcohol content using SAFE-GC-O/AEDA and OAV calculation.

Wooden barrel aging has currently been used to increase the flavour complexity of beers. To investigate the aroma evolution of beer with high alcohol content after bourbon barrel aging, the aroma of beer before and after aging (BBA and BAA) was comparatively studied at both sensory and molecular levels. QDA revealed that BBA was characterised by a pronounced "fruity", "caramel-like", "wine-like" and "alcoholic" aroma, whereas BAA was rich in "coconut", "woody", and "vanillin" notes. Thirty-three odourants with OAV > 1 were identified and verified. Both additive and subtractive aging took place during bourbon barrel aging and 12 odourants were screened by Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) and validated by spiking experiment as potential odor-active markers for BBA and BAA discrimination. The molecular insights into the effect of bourbon barrel aging on beer aroma provided herein will provide guidance for beer aroma quality control and for aroma evolution mechanism investigation.