Whole cluster fermentation

An increasing number of wine labels tout “whole cluster fermentation.” What does that mean and should you care?

Most often found on pinot noir and syrah offerings, the meaning almost is self-explanatory. Grapes are not separated from the stems (de-stemmed) and the entire grape cluster goes into the fermentation tank. In contrast, the majority of wineries remove and discard stems before crushing and fermentation.

Stems provide their own distinct flavors, tannin, and structure. Under-ripe stems contribute vegetal and herbal notes. Ripe stems bring spice, black tea, forest floor nuances. Stems also can lighten the color of the wine by absorbing pigments, creating a brighter looking wine.

Whole cluster fermentation encourages a limited amount of carbonic maceration, where fermentation begins inside the grape before the crush. That evokes more fruit, reduces tannin, and improves mouthfeel.

Burgundy and the Rhône are most associated with whole cluster fermentation because the technique can provide a broader mouthfeel for pinot noir and can complement the meaty flavor of syrah. New World wineries have increased use of the technique for those same varieties and are more likely to announce the technique on their labels.

Even the most ardent whole cluster proponents ferment only two-thirds of the juice as whole clusters, many others less. Advocates believe the technique engenders silkier tannins, greater complexity, and better aromatics. The downside is whole-cluster wines can be awkward in their youth thanks to stem tannins, but that is offset by the belief they are more age-worthy.

In many cases, the decision to go whole cluster is made by winemakers intrigued by the subtleties it can engender. For West Coast winemakers, it is also likely they also are encouraged by marketeers who want to put a new buzz designation on the label. Taste and see what you think.

Tasting notes:

• Mezzacorona Pinot Grigio Trentino DOC 2017: Crisp easy drinker that nails the Italian pinot grigio profile. $9-12 Link to my review

• Willamette Valley Vineyards Whole Cluster Pinot Noir 2017: Sumptuous, slurping drinkability, eloquent fruits, graceful mouthfeel. $17-20 Link to my review

• Willamette Valley Vineyards Whole Cluster Rosé of Pinot Noir 2017: Fresh, bright, delicious. Excellent mouthfeel and engaging fruit. $16-20 Link to my review

E. Guigal Côte-Rôtie Brune et Blonde de Guigal 2012: Outstanding expression of Côte-Rôtie syrah-viognier blend. $61-78 Link to my review

Last round: Ninety-eight percent of wine snobs give the rest of us a bad name.