Winemaking Takes a Plunge

Winemaking doesn’t normally require a snorkel, but experiments in underwater winemaking in France, Italy, Spain and Greece may have vintners reassessing their gear. By playing with the parameters of how wine is fermented and aged—oxygen exposure, temperature, darkness, pressure and agitation—winemakers are using the sea to rethink how we make great wine.

“Of course, if people want to put all the wine in the world underwater, it’s going to get complicated,” said winemaking consultant Michel Rolland. “But is there an effect from submerging the wine? Certainly.”

In June 2011, Bruno Lemoine, director of Château Larrivet Haut-Brion, chained a 56-liter new oak barrel filled with his 2009 Merlot-Cabernet blend to an oyster bed owned by his friend Joel Dupuch, an actor and seventh-generation oyster farmer. “I didn’t know what to expect. I was afraid it was complete nonsense, but we were very, very pleasantly surprised,” said Lemoine.

The oyster-bed barrel, dubbed Neptune, spent six months immersed in Arcachon Bay, partially exposed to air for an hour a day at low tide. High tide put the barrel 20 feet under. The wine also weathered the bay’s legendary current. “Twice a day there is this enormous mass of water—800 million cubic meters—that comes and goes to the Atlantic,” said Dupuch. Meanwhile, a similar 56-liter new oak barrel, named Tellus, aged the usual way in the cellar in Leognan.

In January 2012, the barrels were reunited on land and analyzed by Rolland’s lab. Tellus had a more youthful color and better polymerization of tannins due to the micro-oxygenation in the cellar, while osmosis between the sea and the wine gave Neptune a touch of salt that masked bitterness and heightened flavors, a slightly lower degree of alcohol and rounder tannins.

“The wine that was in the submerged barrel was clearly better—more complex, more intense than the wine that was aged in the château’s cellar. It was inarguably a completely different wine,” said Rolland. “We have a more approachable-tasting wine, and the tannins are much softer, they seem older.” Intrigued by the sea, Rolland is also consulting on a deep-sea cellar, 124 miles off the Atlantic coast at a depth of 3,280 feet.

One of the first to take the underwater wine plunge was Emmanuel Poirmeur, owner of Egiategia in the French Basque region, who in 2007 began putting his sparkling wine underwater during secondary fermentation. Piero Lugano, owner of Bisson winery on Italy’s Ligurian coast, began making spumante underwater in 2009 because he didn’t have adequate cellar space. “My imagination led me to the idea of the seabed as a perfect wine cellar,” said Lugano. He loaded 6,500 bottles into a metal cage and lowered it 196 feet into the sea off the Portofino Marine Park, where it rested for 16 months.

“The result was amazing, beyond my expectations! It shows a very intense color. The bubbles are fine and persistent. The aromas are very clean and delicate. The flavor is dry, clean, very savory and long.” Four vintages and 26,000 bottles of Abissi (Italian for abyss) later, Lugano believes the absence of oxygen and slight cradle effect, created by strong currents, encourage the optimal development of aromas.

He may be on to something, said Denis Sergent, Ph.D., technical manager for synthetic cork maker Nomacorc. The question is how wine handles a reductive environment—Sergent describes it as nano-oxygen rather than zero-oxygen. “It’s crazy, but in fact, it’s really interesting,” said Sergent about the underwater experiments. “Oxygen is the most significant factor in these trials, followed by steady, low temperatures and no light.”

Sergent spends his time worrying about oxygen—specifically, how much oxygen a wine needs, over how much time, in order to achieve aromas, flavors and structure. Nomacorc got involved in underwater wine when Laurent Maynadier, owner of Château Champs des Soeurs in Fitou, asked Sergent to taste two of his Corbieres blancs. One was a control sample from his cellar, and the second had spent three months 33 feet down tied to an oyster bed in the Mediterranean.

“It was amazing. I thought the guy was showing me two completely different wines,” said Sergent. “The white wine that had spent three months underwater was clearly better. It had these yellow-green glints and a nose of citrus and grapefruit. The wine that had stayed in the cellar had none of that.”

Maynadier conducted a second trial with both red and white wines at a depth of 65 feet for six months. “It was too long for his white wine. There were more reductive aromas, which are swampy and cabbage-like,” said Sergent. “But the red wine aged under water for six months was fresher, more complex [than the land-aged sample] and very, very beautiful. The tannins weren’t as mature, but the aromas were fresh.”

The implication for Sergent is that Maynadier’s white wine improved with a short, cool, reductive aging, but it was a delicate balance. The red wine, however, thrived in an environment with less oxygen than it currently gets in the cellar. “What this shows is that the role of oxygen is crucial,” said Sergent. Varying levels of nano-oxygenation may help winemakers find the best expression of their terroir.

Few winemakers have the research-and-development resources of Josep Bujan, head winemaker at Freixenet, the Spanish sparkling wine giant, which produces 200 million bottles of cava a year. This spring, Bujan’s team will work with a diving company to submerge 500 bottles of cava at 80 to 100 feet under the sea to collect their own data on underwater secondary fermentation and aging. Half of the bottles will use crown caps, and half will use natural cork. “Our aim is to see the evolution of the wine,” Bujan told Wine Spectator. “There are many opinions, but nothing has been done as a real test.”

Gerard Liger-Belair, a Reims University-based bubble expert, says that cool temperatures slow secondary fermentation, which may have an effect. “I have heard that slow secondary fermentation produces fine bubbles, but nothing has been proven yet scientifically. We will need several years to analyze the data.”

The tidal stirring of the lees could also lead to a more homogenous repartition of yeast, and thus a more homogenous dissolution of carbon dioxide. “I really would be delighted to get samples of wine fermented underwater with the same level of sugar as those fermented in traditional cellars, in order to scientifically compare the bubble size between them,” said Liger-Belair.