Use of Zirconium Dioxide during Fermentation as an Alternative to Protein Fining with Bentonite for White Wines

Zirconia pellets (25 g/L) enclosed in a metallic cage were added on the second day to fermenting Riesling, Sauvignon blanc, and Semillon juices. After 48 hours, the zirconia-treated juices showed a large decrease in protein content and the resulting wines were heat stable. Compared to control juices, the fermentation rate was significantly increased for two juices and unchanged in the other juice. There were reductions in concentration of some mineral elements and tartaric acid and increases in pH in the resulting wines from the zirconia-treated juices.