Optimization of the Operating Conditions for Color Correction in White Wines Based on the Use of Yeast as Fining Agent

Sherry-type pale white wines were subjected under different stirring times to color correction treatments based on the use of variable concentrations of free yeast and a single concentration of yeast immobilized on carrageenan gel. At all concentrations tested, the free yeasts decreased the A420 of the initial wine. The immobilized yeast showed slightly lower effectiveness to retain browning compounds of the wine and exhibited no significant differences among the treatment times assayed. Choosing the most unfavorable conditions (24 h), significant decreases in the concentrations of low-molecular-weight phenolic compounds were observed. The sensory properties of the wines treated with the immobilized yeast were shown to be similar to those of wines treated with activated charcoal for flavor, better for color, and slightly worse for aroma.