Stems: to include or remove

Destemming became near-universal in the twentieth century and has been partly reversed since, particularly in Burgundy, the Northern Rhône and among Pinot Noir producers elsewhere.

Whole-bunch fermentation is the related but distinct practice of including whole intact bunches, which brings stems along with a partial carbonic effect.

Stem tannins differ from skin and seed tannins and are generally described as more astringent and less rounded, particularly when the stems are green.

Stems absorb some alcohol and some colour, which is why heavily stemmed ferments can be slightly paler and marginally lower in alcohol.

They also contribute potassium, which raises pH. That is a real consideration in warm regions where pH is already high, and much less of one in cool ones.

The aromatic contribution is commonly described as herbal, floral or spicy, and it interacts with the carbonic effects that whole bunches also produce.

Physically, stems create channels through the cap, which improves drainage during pressing and can moderate fermentation temperature.

Ripeness of the stem — brown and lignified rather than green — is the variable most producers name as decisive, and it does not track fruit ripeness reliably.