Effect of Wine-Making Practices on the Concentrations of Fenarimol and Penconazole in Rosé Wines

The changes in and influence of the anti-powdery-mildew fungicides fenarimol and penconazole were studied in the production and quality of rosé wines made with Monastrell grapes grown in the Jumilla wine-producing region in SE Spain. Fungicide concentrations were estimated by gas-liquid chromatography with electron-capture detection. Fermentation was retarded more by penconazole than by fenarimol; in both cases, the slowdown was directly proportional to fungicide concentration. However, the mature wine contained normal concentrations of residual sugars; other enological parameters (pH, volatile acidity, intensity of color and hue) were not significantly affected. Thirty-four days after the start of the experiment, 67% of fenarimol and 52% of penconazole, with respect to the smaller amount initially added (1 mg/liter), were found in the finished wine. The calculated half-life times were 45 and 59 days for penconazole and fenarimol respectively. Different wine-making techniques (racking, clarification, and filtration) had no decisive influence on the removal of fungicide residues from the must, although they eliminated slightly more penconazole than fenarimol.