For several years, no topic has divided Burgundy’s winemakers as much as the issue of fermenting with stems – also known as whole-bunch or whole-cluster fermentation.
On one side of the debate are producers like cult winemaker Étienne de Montille of Domaine de Montille, who is extremely keen on the technique.
“I love stems and we use a certain amount of them in every vintage, and in every tank, ranging from 0 percent to 100 percent," says Montille. "I think stems give the wines a spice and floral character to the wines as they age."
Other producers, however, are quick to defend de-stemming the bunches before fermentation, including Dominique Lafon of Domaine des Comtes Lafon. When asked his opinion on whole-bunch fermentation at a Burgundy seminar organized by Institute of Masters of Wine in London earlier this year, Lafon reportedly responded: "Every time I've tried it, the wine was not as good as when I de-stemmed."
While the debate over whether to de-stem or not has spread across the globe into New World pinot noir strongholds such as New Zealand, another celebrated Old World region is also experimenting with the technique. In Italy’s Barolo and Barbaresco denominations in the Langhe hills of Piedmont, producers are testing out whole-cluster fermentation. One of the most famous is celebrated Barbaresco producer Angelo Gaja.
“In 2009, the stems from our Barbaresco vineyards were perfectly mature, so we decided not to de-stem bunches from certain vineyards,” says Gaia Gaja. “I love the results. Fermenting with the stems, when they are perfectly ripe, adds more complex aromas including spicy notes and Alpine herbs. Because the stems can take away some color, we had to have a longer maceration period and in the end, whole bunch fermentation gave the wine another dimension.”
However, Gaja adds a cautionary note: “Whole-cluster fermentation can only be done when the stems are perfectly mature.”
She adds that she, her father, and their winemaking team were so pleased with the results that they are now experimenting with whole-cluster fermentation with sangiovese at their Brunello property, Pieve Santa Restituta.
Over in Barolo, Monforte d’Alba cult producer Ferdinando Principiano, one of the early proponents of the natural-winemaking movement in Italy, is also a fan of whole-cluster fermentation – but only under the right circumstances. Without de-stemming, Principiano crushes grapes from 40-year-old vines from his Barolo Boscareto vineyard in Serralunga d’Alba, and then ferments with no selected yeasts.
“You can ferment with whole clusters only when vineyards are treated naturally and have perfect growing conditions – including ideal exposure – because these vineyards can yield healthy, ripe grapes and bunches,” says Principiano. "When stems are perfectly ripened, they add noble tannins to the wine."
Prunotto, another prestigious Barolo house now owned by the Antinori family, is also trialling whole-bunch fermentation. “Our Barolo Riserva Vigna Colonnello 2008 was fermented with the stems,” says managing director Emanuele Baldi. "That year, the stems were perfectly ripe and we decided to try it too. We are very pleased with the complexity of this wine, which had a long maceration period of 35 days.
Baldi notes that "to get fine tannins, the stems have to be ripe, otherwise they can generate green tannins,” and points out that stems do not always ripen well.
However, not all Barolo producers agree that fermenting with stems has any benefits, and many are highly critical of the technique, including Franco Massolino of Massolino–Vigna Rionda.
“Nebbiolo is already a very tannic grape, and it has extremely fragile stems that easily break into numerous small pieces," he says. "The first generation of de-stemmers didn’t work well for nebbiolo because the broken bits of stems still got into the fermentation tanks.
"Over the last two decades, my family – like most producers in Barolo and in Barbaresco – have not only drastically changed how we manage our vineyards to achieve ideal grape ripening, but we’ve also invested heavily in technology in efforts to produce wines that have less-astringent tannins than Barolos produced up until the 1980's.”
According to Massolino, one of the most important investments has been acquiring avant-garde crusher/de-stemmers that permit soft pressing and gentle de-stemming, which he feels is fundamental to making Barolo with firm but ripe tannins. “I’m convinced that de-stemming gently and entirely gives our wines fine tannins without the astringent, green tannins that Barolo was famous for until we had this technology.”
Massolino admits he’s never tried whole-bunch fermentation – and isn’t likely to either. “No matter how ripe, I still think stems are going to add astringent tannins.”
Although the vast majority of Piedmont producers agree with Massolino, more and more are experimenting with the idea. One reason may be global warming. According to famed Italian consultant oenologist Donato Lanati’s book "De Vino," stems absorb alcohol. As climate change pushes up temperatures and alcohol levels, we may see more producers opting for the whole-cluster route.