PRODUCTION OF BOTTLE-FERMENTED SPARKLING WINE USING YEAST IMMOBILIZEDIN DOUBLE-LAYER GEL BEADS OR STRANDS

Bottle-fermented sparkling wines were produced using Saccharomyces cer evisiae immobilized within double-layer calcium-alginate beads or stra nds, and some factors affecting the leakage of viable cells from the g el into the wine during fermentation and aging were investigated. Yeas t immobilized in beads or strands at 10(4), 10(6), or 10(8) cells/mL w as added to 740-mL samples of a base wine containing 24 g/L sucrose, a t ethanol concentrations of 0.5%, 3%, 6%, 9%, or 12% (v/v). Secondary fermentation was conducted at 15 degrees C or 25 degrees C in 770-mL b ottles with a pressure gauge. Fewer free yeast cells appeared in the w ines the higher the initial number of immobilized cells or the initial ethanol concentration. Wines fermented with yeast immobilized in gel beads contained greater numbers of yeast cells than those immobilized in gel strands, but no free viable yeast cells remained in the wines a few months after fermentation in either case. Beads would be preferab le to strands in commercial production because they were much more eas ily added to and removed from bottles via the ice disgorging procedure commonly used in the production of Champagne, without the need for th e traditional riddling. Sparkling wine was also made using freely susp ended yeast, and changes in the chemical components, including amino a cids, during aging of wines made with free and immobilized yeast were investigated and compared. There were no significant chemical differen ces between the two. It was thus concluded that secondary fermentation of sparkling wines using yeast immobilized within double-layer algina te beads is practical for commercial production.