Brettanomyces anomalus is shown here to metabolise p-coumaric, caffeic and ferulic acid to 4-vinyl and 4-ethyl derivatives. We also demonstrate the transformation of vanillin to both vanillyl alcohol and vanillic acid by this yeast. The results presented here show the production of these compounds during the fermentation of this organism and also the effects of these and other simple phenolic compounds on the growth of the organism. The products were analysed and their identities were determined by TLC, HPLC and by mass spectrometry.