This study examines the impact that fermenting with whole clusters or with stem inclusion has on Chambourcin wines. Chambourcin grapes were harvested from the same block on the same day and separated into 3 T Bins. One T Bin received 100% destemmed and crushed fruit (control). The second T Bin received 30% whole clusters at the bottom, and then was filled with 70% destemmed and crushed fruit (by weight). The third T Bin received 30% of the stems by weight from the control at the bottom of the T bin, and then were filled with the same weight of destemmed and crushed grapes as the control and treatment. All other treatments between musts and wines were identical. pH was slightly increased by whole cluster and stem inclusion, and TA and tartaric acid was slightly decreased. Pyrazine was slightly increased by the treatments. Color intensity was not much affected by the treatments. Catechin, epicatechin, and quercetin were slightly increased by the treatments. Tannin was increased by the treatments, and anthocyanins were decreased by the treatments. Overall, stem inclusion seemed to result in lower Bitterness, and may have lowered Astringency and Herbaceous/Green character. The whole cluster and the control treatments tended to be higher in Herbaceous/Green character. The intensity for the descriptors for whole cluster inclusion seemed to change over time, perhaps due to ester qualities decreasing over time in bottle. Preference trends were hard to determine, although whole cluster and stem inclusion wines tended to be more preferred over the control.
This study examines the impact of cold soaking vs extended maceration on Petit Verdot wine, with maceration time being equal between treatments. The goal was to have on treatment spend more time exposed to an aqueous phase, with the other treatment having more time exposed to an alcoholic phase. Petit Verdot grapes from the same vineyard block were harvested on the same day and destemmed into two separate T Bins. One T Bin underwent a 4 day cold soak prior to inoculation, whereas the other was immediately inoculated without cold soak. Both treatments underwent a 25 day maceration before being pressed off on the same day: thus, the cold soak received less time in contact with must in an alcoholic phase. All other treatments between wines were identical. Wine chemistry and ester profiles were not much different between treatments. The extended maceration treatment had higher levels of color, epicatechin, and tannin, but other phenolic compounds were not much different. The wines were not found to be significantly different via triangle testing. However, there was a strong trend for the cold soak wine to have higher Astringency than the extended maceration wine. There was a slight tendency for this wine to have increased Bitterness and lower Body as well. The total maceration time for these wines was long in both cases, and as such the differences seen here may be greater if smaller overall maceration times are used. In the future, this should be performed, and more microbial analysis should be performed as well.
This study compares the effects of CelStab (Laffort) on the tartrate and colloidal stability of Vidal Blanc vs traditional cold stabilization. Vidal Blanc grapes were whole cluster pressed and fermented normally. After fermentation, samples were taken for heat and cold stability in November, and later the wine was bentonite fined and then sterile filtered into two separate vessels. One vessel received traditional cold stabilization at 28°F, and the other vessel had CelStab added at 1mL/L to induce chemical tartrate stabilization. All other treatments between wines were equal. Both treatments increased cold stability, but traditional cold stabilization had a greater impact in this case. Other wine chemistry was not affected by the treatments. Wines were not found to be significantly different via triangle test. There were no strong preference or descriptive trends between wines.
This study examines the impact of whole cluster inclusion on the phenolic and sensory characteristics of Chambourcin wines. Chambourcin grapes sourced from the same block were either completely destemmed and lightly crushed (0% inclusion), 70% were destemmed and lightly crushed (30% inclusion), or 50% were destemmed and lightly crushed (50% inclusion). All other treatments between lots were the same. Increasing the amount of whole cluster inclusion tended to lower the ethanol content. Whole cluster inclusion tended to lower the color intensity and increase the hue, and this effect was more pronounced for higher levels of inclusion. All phenolic indices were lowered by whole cluster inclusion, but did not differ much between 30% and 50% inclusion. This was most noticeable with monomeric and total anthocyanins, as well as malvidin glucoside. Overall, whole cluster inclusion tended to increase Herbaceous/Green character in the wines. Descriptions of these wines were mixed, and most trends were weak and varied from tasting to tasting. No major preference trends could be seen across tastings. This study suggests that whole cluster inclusion could be a viable stylistic tool for Chambourcin wines, but much more work is needed to elucidate what impacts these kinds of treatments have on wine quality.