José Cuevas-Valenzuela* and Álvaro González-Rojas 
*Center for Research and Innovation, Viña Concha y Toro, Ruta K-650 S/N, KM 10, Pencahue, Talca, Chile (jose.cuevas@conchaytoro.cl)

“Greenness” in wines can be defined as the perception of herbal and vegetal flavors, considered undesirable sensory attributes in red wines. These green characters are partially related to the presence of methoxypyrazines, C6 alcohols (trans- and cis-3-hexen-1-ol), and aldehydes (hexanal). Flash Détente (FD) is a technological process that uses a heat exchanger coupled to a vacuum flash evaporation chamber to rapidly heat grapes and remove volatile compounds, leaving a concentrated must and a condensate. Before fermentation, the must can be mixed with the condensate, which must be previously treated with activated carbon to remove undesired compounds. We evaluated the capacity of FD for reducing the “greenness” in Chilean Cabernet Sauvignon wines without affecting other quality aspects. Three treatments were addressed: red winemaking without FD (control), red winemaking of FD-treated grapes (T1), and white winemaking of FD-treated grapes (T2). The pH, acidity, ethanol, total phenols, and color index of each resulting wine were measured using standard techniques. Concentrations of methoxypyrazine and C6 compounds were measured using GC-MS/MS. Sensory analysis evaluated the impact of treatments on wine quality and “greenness”. T1 wine had a greater color index and more total phenols than the other treatments. No significant differences in hexanal were found among treatments. Trans- and cis-3-hexen-1-ol concentrations were significantly lower in T1 and T2 wines than in the control. Methoxypyrazine measurements are under statistical analysis. T2 wine had significantly lower levels of green bell pepper, cut green grass, and vegetal aromas than control wine. Also, it had greater levels of fruit aroma, juiciness, and global quality. FD is thus an effective prefermentation technology to produce wines with reduced “greenness.”

Funding Support: Viña Concha y Toro