Caroline Merrell and James Harbertson*
*Washington State University, Wine Science Center, 2710 Crimson Way, Richland, WA 99354 (jfharbertson@wsu.edu)

Extended maceration is a technique used by winemakers to increase phenolic extraction in wines. While this technique is typically used for short periods of time, recent winemaking trends have given rise to extraordinary macerations, up to eight to nine months. In this study, Cabernet Sauvignon was picked at three different maturities, representing unripe, ripe, and overripe fruit. Control and extended maceration tanks were fermented in triplicate (140 L scale) and extended maceration wines were allowed to age on the skins for up to eight months. Samples were collected throughout maceration, and at each time point, samples were aged at elevated temperatures to simulate aging.  Accelerated aging was used to predict phenolic changes over time if the wine was pressed after any length of maceration. At each maturity, tannin extraction reached a maximum after 60 days maceration. After 60 days, all extended-maceration wines had a similar tannin concentration, although wine alcohol levels were significantly different. At each harvest, concentrations of color-related phenolic compounds followed similar trends over time. Anthocyanin content decreased postfermentation in both control and extended-maceration wines, but the decrease was slightly greater in extended-maceration wines. While extended maceration did not increase the anthocyanin concentration, it did alter wine color (as observed by tristimulus color measurements), due to the formation of polymeric pigments. Phenolic hydrophobicity, measured to determine phenolic structural differences, depended on maturity and time, but not winemaking treatment.  During accelerated aging, large polymeric pigment increased with maceration time as tannin concentrations increased.  However, small polymeric pigment followed similar trends regardless of maceration time. Overall, extended maceration increased tannin extraction and large polymeric pigment formation across all harvest dates.

Acknowledgements: Richard Larsen, Maria Mireles, and WSU graduate students and interns are thanked for winemaking assistance and harvest laboratory analysis.

Funding Support: Funding for this project was provided by the Washington Grape and Wine Research Program and the National Institute of Food and Agriculture.