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Ageing wine underwater: explained

Constant temperatures, guaranteed darkness and tidal movements – is ageing wine underwater the way of the future? David Kermode investigates the trend for sea-aged Champagne and still wine

Words by David Kermode

drappier wine bottles covered in barnacles after being aged in the sea
The Collection
Champagne Drappier's Immersion cuvée is aged in the Atlantic Ocean

In its beautiful barnacle-encrusted bottle, a wine aged on the ocean floor might conjure up a sepia image of shipwrecked treasure, or even suggest some bygone quackery – yet the reality could not be more different. It is the physical manifestation of winemaking ingenuity. The relatively risky technique is still rare to see – with the resulting cuvées priced accordingly – since its modern origins stem from the 170-year-old Veuve Clicquot bottles that still had their sparkle in 2010, when discovered among the remains of a sunken schooner. That shipwreck left a lasting legacy in the inspiration it offered restless winemakers.

Underwater-aged wines command premium prices, and the technique is most closely associated with Champagne

Today, it is possible to find several dozen different cuvées, both sparkling and still, aged underwater – usually in the sea, though sometimes a lake. Such wines command premium prices, so it is little surprise that the technique is most closely associated with Champagne. But there’s more to the attraction for sparkling winemakers. ‘There is, in my view, a clear correlation between the ambient pressure enjoyed during élevage [the development of a Champagne], underwater or otherwise, and the putative longevity of a sparkling wine,’ says Master of Wine and Champagne expert Simon Field. ‘Under pressure, the slow work of autolysis becomes more focused, and accordingly, the wine has more definition and character,’ he adds.

How does ageing wine underwater work?

Pressure plays the critical role in underwater ageing, with around 1 bar per 10m of depth. Therefore, at between 50 and 60m, the pressure outside a bottle of submerged Champagne broadly equals that within. This means that oxygen is banished and carbon dioxide cannot escape, while the autolytic reaction that gives sparkling wine its distinctive character is faster and, seemingly, more profound.

Water temperature under the ocean is part of the appeal, too, since it is relatively constant and also similar to that found in the deep chalk cellars of Épernay or Reims. Darkness is guaranteed on the seabed, eliminating any risk of lightstrike, and there’s a final, spellbinding ingredient: the stirring motion of the ocean, something Leclerc Briant’s winemaker Hervé Jestin, a pioneer of the process, likens to ‘permanent dynamisation’.

Leclerc Briant submerges its Cuvée Abyss off the coast of Brittany

Leclerc Briant’s Cuvée Abyss spends between 10 and 15 months ageing on the sea floor (depending on the vintage), close to the island of Ouessant, off the coast of Brittany. It is one of the finest examples of the technique, its scintillating purity and ethereal fruit frozen in time, while its subtle streak of salinity seems uncannily connected to the barnacles on the bottle. ‘After a year in the deep, in a permanent state of tidal movement, the wine develops profound energy and uplifting harmonic character,’ says Davy Zyw, senior buyer at Berry Bros & Rudd, the UK importer for Leclerc Briant Abyss. ‘It has the purity of fruit, complexity and drinkability equal to other Leclerc Briant cuvées, but Abyss’s mineral edge is unquestionably salty and undeniably stimulating.’

Darkness is guaranteed on the seabed, and there’s a final, spellbinding ingredient: the stirring motion of the ocean

Amid the rising tide of Champagne houses sinking their coveted cuvées, Champagne Drappier also chose the Atlantic to create Immersion. ‘Ageing wine under the sea allows for a constant temperature and ideal obscurity, with the motion of the waves assisting the process,’ says Michel Drappier, who believes the balance of pressure also results in purer, more refined bubbles.

Drappier also favours the Atlantic for the maturation of its Immersion Brut Nature

Not to be left behind, England’s sparkling pioneers have also been plumbing the depths while simultaneously raising the stakes. Exton Park has chosen to underwater-age its Blanc de Blancs 2014 on its lees (yeast cells), rather than after disgorgement. The rules stipulate that a Champagne must be disgorged before it leaves the region but such strictures do not apply to wines made within the UK.

Is it just Champagne that benefits from ageing on the seabed?

Though sparkling wine has made the running, there have also been successful experiments with still wines in Spain, Chile, California and on the Greek island of Santorini, where Gaia has created its Thalassitis Submerged Assyrtiko under the Aegean. The experiment began in 2009 and got off to an inauspicious start when violent storms destroyed all but a few bottles. A further setback occurred two years later, when most of the corks gave way to seawater. However, lessons have been learned, and its most recent vintage (2018) is both breathtaking and baffling in equal measure, combining freshness with the satisfying complexity usually associated with oxidative ageing.

Gaia uses the Aegean Sea to experiment with ageing Assyrtiko underwater

Gaia’s winemaker Yiannis Paraskevopoulos, a keen diver, is convinced the process makes sufficient difference to warrant the risks. ‘The inherent flintiness of Assyrtiko becomes amplified greatly, to generate an intense fuel-like character, much like that of an aged Riesling,’ he says. He also claims that, as they dissipate, those aromas give way to floral and sweet honey notes, unfamiliar territory for an unoaked Assyrtiko from Santorini. ‘Even more interesting is the fact that those aromas are not the product of the slow oxidation that is associated with ageing, because that is simply impossible.’

Is ageing wine underwater more than just a fad, then?

So, is underwater ageing the future? There is no shortage of space for it (though the seabed must be leased and off limits for fishing trawlers), and the process of temperature control is natural, after all. The thirst from curious collectors currently appears unquenchable, despite some initial fears that the technique owed more to the vagaries of fashion than the parameters of science.

Pierre Bettinger, Leclerc Briant’s sales director, insists underwater ageing is anything but faddish. ‘It fits well with our philosophy. We’re working with nature to have the perfect ageing conditions.’