Lipolytic enzyme variants with increased specificity for short-chain fatty acids can be designed on the basis of a three-dimensional model of a lipolytic enzyme such as C. antarctica lipase A with a substrate analogue such as a fatty acid. An amino acid residue is selected within 10 Å of the carbon atom corresponding to the desired chain-length specificity, and the selected residue is substituted with a larger residue, or an amino acid insertion is made adjacent to the selected residue.