Sensory differentiation among rosé wine styles using Merlot, Pinot noir, and Dornfelder grapes sustained well the dealcoholization process

Abstract

According to the OIV, consumption of rosé wines exceeded worldwide production by 6% (1). These figures stimulated the experimental vinification of 3 different rosé styles for each of the cultivar Merlot, Pinot Noir and Dornfelder. The “Provence” style, aiming for pale color and light body applied whole cluster pressing, no use of SO2 in grape processing and flotation with air. The equally processed “Fumé” style fermented with an early autolyzing yeast in presence of 0.5 g/L oak chips, followed by weekly bâtonnage. For the “Thiol” style, crushed grapes were processed in presence of SO2/ascorbic acid and fermented by a thiol releasing strain. All wines passed malolactic fermentation by a lactobacillus plantarum strain and were bottled with 1.9 g/L CO2 (2). Descriptive sensory analysis and PCA revealed a clear distinction among colorful Dornfelder rosé wines, while paler Merlot and Pinot noir plotted in proximity being more sour and mineral. Hierarchal cluster analysis (HCA) classified the rosé style as the dominating factor for Merlot and Pinot Noir, while all 3 styles clustered together for Dornfelder. Thus, Merlot and Pinot Noir are well suited for the pale “Provence” style, while Merlot and Dornfelder yield more pronounced “Thiol” rosé wines with higher grapefruit intensities. The impact of oak and yeast autolysis was stronger perceived in Pinot Noir and Merlot, while Dornfelder yielded a more colorful version. All 9 rosé wines were dealcoholized by vacuum distillation in January of the following year. Sweetness was equally adjusted to 30 g/L, using neutral rectified grape concentrate to avoid color changes. Although sensory intensities declined due to ethanol removal, the specific characters of each rosé style were well resembled in the dealcoholized versions. HCA grouped first rosé styles of varying alcohol levels together, followed by the three cultivars. Pinot Noir rosé wines showed the smallest differences among alcoholic vs. non-alcoholic wines, followed by Merlot, while Dornfelder yielded the largest differentiation. Regarding wine styles, the smallest deviation was observed for the “Provence” style, followed by “Thiol” and “Fumé”. Volatiles, including thiols, are currently analyzed in non- and alcoholic wines and will be presented as well. In conclusion, all grape varieties were highly sensitive to oenological measures to differentiate three distinct rosé styles. Differences among styles and cultivars were well preserved after alcohol removal.

References

(1) Anonymus (2024). OIV-FOCUS-2023: Evolution of the world wine production and consumption by colour. 1-44.

(2) M. Blank et al. (2024). CO2 im Stillwein. Das deutsche Weinmagazin, 2024(7), 2024, 18-24.