This study examines the impact of whole cluster inclusion on the sensory and chemical profile of Merlot. Merlot was harvested from the same vineyard block on the same day and processed identically except that one treatment was only 70% destemmed (not crushed) with the other 30% of fruit added as whole clusters. All other treatments were the same. Whole cluster inclusion did not affect wine chemistry, except for slightly increasing pH. Whole cluster inclusion lowered color intensity, anthocyanin content, quercetin, caftaric acid, and epicatechin. However, tannin and catechin content was slightly increased by whole cluster inclusion. Hue was also increased, due to the lower absorbance at 520. Judges found the wines to be significantly different (p<0.01), but no real preference trends could be seen between treatments. 30% whole cluster inclusion tended to score slightly higher in all attributes except for Fruit Intensity and Astringency, where it was the same as 0% whole cluster inclusion. However, the differences for these descriptors were very small, and more studies are needed to identify in what ways the wines can be described as different.
This study examines the impact of whole cluster/stem inclusion on the sensory and chemical profile of Cabernet Franc. Cabernet Franc was harvested from the same vineyard block on the same day and processed identically except that stem inclusion was performed so that either 100% of the fruit was destemmed but not crushed, 60% of the fruit was destemmed but not crushed (40% added as whole clusters), or 10% of the fruit was both destemmed and crushed and the other 90% was added as whole clusters. All other treatments were the same. The 40% Inclusion treatment was not tasted. Whole cluster inclusion did not affect wine chemistry. Color intensity and hue were both increased at 40% and 90% whole cluster inclusion. Cinnamic acids, catechin, tannin, and polymeric anthocyanins were also increased with 40% and 90% inclusion (although polymeric anthocyanins were not very different). Epicatechin and anthocyanins were lowered by 40% and 90% whole cluster inclusion. The results for 40% inclusion were taken at different time points, however, so may not be entirely representative. Judges found the wines to be significantly different, but there were no strong preferences for one treatment over another. 90% inclusion had a slight tendency to have higher Overall Aromatic Intensity and Fruit Intensity, but this was not seen at all tastings. More studies should be performed on whole cluster and stem inclusion to determine how to best vinify different treatments. This is especially true with regard to microbial stability, as well as finding optimal ranges of cluster/stem inclusion based on desired styles.
Cabernet Franc was made with 0% and 25% whole cluster inclusion. There were no chemical differences between wines in this study. The wine made with whole clusters had less anthocyanins and pigment, and slightly less color intensity and greater hue. There was no significant sensory differences between the wines, but people tended to prefer the wine with whole cluster inclusion.