Vine stems

To destem or not to destem? Crushing wine world question.

Look for “whole cluster fermentation” on the label. This is technique where entire grape bunches—including stems—go into the fermenter. Grapes do not go through a destemmer-crusher machine to destem individual berries and crush out the juice.

Advocates of whole cluster assert it produces wines with more complexity, adds herbal and spice flavors, improves fruit flavors, tones down high acidity, adds tannin structure.

Lighter, thin-skinned varieties—pinot noir, gamay, and grenache—are suited for this technique. The practice is most common in Burgundy and Willamette Valley with pinot noir. The Northern Rhône is another place where it is favored to enhance savory qualities and peppery notes of syrah.

Stems can add a “candied” effect, a flavor compared to bubblegum fruitiness. Carbonic maceration, where grapes ferment inside the skins, also delivers this flavor. Gamay often sees carbonic maceration, but since there is not much juice-stem contact, there are gamays that are 100% whole cluster fermented but the stem influence is slight.

Often only some of grapes are fermented with stems attached, so whole cluster is just a part of a winemaker’s recipe. Stems deliver significant tannins, requiring intense fruit for balance. Stems deliver potassium which chemically binds with tartaric acid, lowering acidity and requiring acidic grapes to retain freshness. The more mature the stems—brown and woody instead of green—the more subtle the influence.

Stems engender a green-herbaceous element that, in moderation can be a plus, but in excess ruins a wine. Whole cluster requires powerful fruit, but not fruit that leans toward herbaceous. That is why cabernet sauvignon and merlot are almost never fermented whole cluster.

Whole cluster fermentation was the only way wine was made for thousands of years. Crude destemmer-crusher machines appeared in the 1800s, but it was only in the middle of the last century they became efficient and widely adopted. The first destemmer-crusher? The human foot.

Tasting notes:

• Broadley Vineyards Estate Pinot Noir Willamette Valley 2016: Excellent fruit; built for food pairing; whole cluster fermentation. $28-35 Link to my review

• Etude Pinot Noir, Estate Grown Grace Benoist Ranch Vineyard, Carneros 2017: Superb year after year; some whole cluster fermentation. $38-47 Link to my review

• Sosie Wines Pinot Noir, Spring Hill Vineyard, Sonoma Coast 2015: Elegant, delicious; 20% whole cluster. $43 Link to my review

• La Crema 40th Anniversary Pinot Noir Russian River Valley, Sonoma County 2018: Exceptional wine; 20-30% whole cluster. $100 Link to my review

Last round: To relieve stress, drink wine while you wear yoga pants.