Changes in the sorption of diverse volatiles by Saccharomyces cerevisiae lees during sparkling wine aging.

The volatile profile of sparkling wine is influenced by the retention and release of volatile compounds by lees during the aging process. Here we attempted to identify the volatiles that are most retained by lees in aging conditions and to study how their sorption varies during aging. We estimated the lees sorption capacity for several representative volatile compounds in sparkling wine samples at a range of time points during aging by assessing the volatiles sorbed on the lees surface and those present in the corresponding wines. The sorption of volatiles was proportional to their hydrophobicity, and their retention by the lees surface changed during aging. The sorption of less hydrophobic compounds decreased after the first 2 months of aging, while that of the most hydrophobic volatiles increased until 18 months, and decreased dramatically thereafter. These results indicate that the length of aging on lees determines the type and the amount of wine volatiles removed with lees in the disgorging step. While most polar aromas seem to be released from the lees surface at the earliest stages of aging, highly hydrophobic compounds and esters in general are progressively retained and subsequently desorbed into wine. Changes in the physicochemical properties of the lees cell surface were monitored during aging, but these could explain only the decrease in the sorption of less hydrophobic compounds.