By Kevin Elder and Elizabeth Higley, Windsor Run Cellars
Effects of Whole Cluster Fermentation on Chambourcin
Summary
The technique of whole cluster inclusion during fermentation is well established in winemaking. This technique is perhaps most used in the production of Pinot Noir, where it is often thought that stem inclusion increases tannins and produces a fresher tasting wine with some herbal aromatics. In this experiment, we wanted to explore the stylistic and chemical differences resulting from Chambourcin 50% whole cluster and 100% whole cluster compared to a destemmed and crushed control. Increasing the whole cluster percentage increased potassium, pH and methoxypyrazine levels in the finished wine. Increasing the whole cluster percentage also decreased anthocyanin and color intensity of the resulting wine. Sensory analysis revealed that the destemmed and crushed wine had more body and less herbaceous/green intensity.
Methods
Chambourcin was hand harvested on October 10, 2023. For the control tank, all of the fruit was destemmed and crushed and pumped into tank with a must pump. For the 50% whole cluster treatment, roughly half of the fruit was lightly foot tread and then dumped into tank, the remaining half was destemmed, crushed and pumped on top. For the 100% whole cluster treatment, the fruit was lightly foot tread and dumped into tank. The tanks were the same size and shape and were filled with roughly the same tonnage of fruit. Immediately after filling the tanks they were inoculated with 25 g/hL VL1 yeast and 5 g/hL Egide . No acid or sugar adjustments were made. The following additions were made to each of the tanks during fermentation: 20 g/hL Powerless Rouge, 25 g/hL VR Supra Elegance, 25 g/hL VR Color. Cap management was performed via “pneumatage” (Pulsair) which involves injecting of large air bubbles underneath the cap which rise up and break up the cap while mixing the tank. Cap management was performed twice daily for the same length of time on each tank. Wines were pressed after 15 days of maceration. A pneumatic press was used with a sequential press cycle culminating in a max pressure of 0.7 bar for each wine. The free run and press wine was combined for each treatment. Wines were allowed to settle overnight in tank and were then racked into neutral barrels of the same age and were inoculated with VP41. Upon completion of malolactic fermentation, 80 ppm of SO2 was added. Sensory analysis of the wines was conducted with a blind and randomized tasting with 45 wine industry professionals. The wines were presented in randomly numbered glasses with three different presentation orders. The participants were asked to rate each wine on a scale of 0-10 for fruit intensity, fruit character (bright/fresh to dark/cooked), herbaceous/green intensity, astringency and body. Scores were analyzed with repeated measures ANOVA.
Results
The destemmed and crushed Chambourcin had a higher starting ⁰Brix, lower pH and lower titratable acidity at the start of fermentation (Table 1). The concentration of potassium and the pH of the finished wines increased with increasing whole cluster inclusion (Table 2). This result would be expected as grape stems are high in potassium which increases pH. The destemmed and crushed Chambourcin had the highest alcohol, likely a result of a higher starting ⁰Brix. Increasing the whole cluster percentage resulted in slight increases in catechin and slight decreases in polymeric and total anthocyanins (Table 3). The increases in catechin could be coming from extraction of the stems and the reduction of anthocyanins may be due to the increased percentage of whole berries in the fermentation thereby reducing extraction from the skins. Increasing the percentage of whole cluster fermentation resulted in increased methoxypyrazine levels (Table 4). Crushed and destemmed Chambourcin wine had higher absorbance at 420 nm and 520 nm indicating higher color intensity (Table 5). CIELab coordinates indicate that the crushed and destemmed wine was darker (lower L*), slightly more purple (lower hue angle) and more intense in color (higher chroma) (Table 6). The crushed and destemmed wine was perceived as having less herbaceous/green intensity and more body (Table 7).
