The stereospecificity of the decarboxylase and ethyl esterase of D. bruxellensis was evaluated by submitting cis- and trans-hydroxycinnamic acids and cis-ethyl hydroxycinnamates to fermentations with D. bruxellensis AWRI 1499. Metabolism of the hydroxycinnamates was preferential for the trans-analogues, and showed that the cis-isomers are unimportant in the accumulation of ethylphenol off-flavor in wine.