AbstractThe fruity odours of wine are largely derived from the synthesis of esters and higher alcohols during yeast fermentation. TheATF1‐ andATF2‐encoded alcohol acetyltransferases ofS. cerevisiaeare responsible for the synthesis of ethyl acetate and isoamyl acetate esters, while theEHT1‐encoded ethanol hexanoyl transferase is responsible for synthesizing ethyl caproate. However, esters such as these might be degraded by theIAH1‐encoded esterase. The objectives of this study were: (a) to overexpress the genes encoding ester‐synthesizing and ester‐degrading enzymes in wine yeast; (b) to prepare Colombard table wines and base wines for distillation using these modified strains; and (c) to analyse and compare the ester concentrations and aroma profiles of these wines and distillates. The overexpression ofATF1significantly increased the concentrations of ethyl acetate, isoamyl acetate, 2‐phenylethyl acetate and ethyl caproate, while the overexpression ofATF2affected the concentrations of ethyl acetate and isoamyl acetate to a lesser degree. The overexpression ofIAH1resulted in a significant decrease in ethyl acetate, isoamyl acetate, hexyl acetate and 2‐phenylethyl acetate. The overexpression ofEHT1resulted in a marked increase in ethyl caproate, ethyl caprylate and ethyl caprate. The flavour profile of the wines and distillates prepared using the modified strains were also significantly altered as indicated by formal sensory analysis. This study offers prospects for the development of wine yeast starter strains with optimized ester‐producing capability that could assist winemakers in their effort to consistently produce wine and distillates such as brandy to definable flavour specifications and styles. Copyright © 2006 John Wiley & Sons, Ltd.