Subsea Estate: Australia’s first underwater winery

Ageing wine underwater has become a hot topic in recent years. Bottles discovered on the seabed among long-forgotten shipwrecks provided inspiration.

On opening, the wine was surprisingly fresh, a testament to the ocean’s powers of preservation.

Several producers have since explored how the ocean might be utilised during the winemaking process.

The most recent winery to release the result of its underwater vinous experimentation is Subsea Estate in Western Australia. The project is a collaboration between Rare Foods Australia and French company Winereef.

Scroll down for notes and scores of wines from Subsea Estate

Winereef’s director and chief winemaker Emmanuel Poirmeur (above) oversees Subsea’s wine production. He developed and fine-tuned the underwater winemaking process since patenting his design 18 years ago.

Prior to co-founding Subsea, Poirmeur produced 200,000 bottles a year. Subsea is one of four Winereefs around the globe; two are in the Basque Country and one in Paris.

Seven more Winereef locations or ‘ocean wineries’ are in development.

Finding the right site

Poirmeur’s search for new locations led him to Augusta in southwest Western Australia, where he met Brad Adams, founder and MD of Rare Foods (below). The company’s abalone farm provided the facilities necessary for Winereef installation.

‘We are working with the ocean, and we are dependent on the ocean, just like Brad,’ explains Poirmeur. The two companies began working together in 2022.

‘We have access to a large area of the ocean here,’ says Adams, referring to an ocean lease of 413ha. ‘We’ve got dive teams and the Margaret River wine infrastructure; the wineries you can partner with to get wine processed easily and bottled easily,’ he explains.

‘It’s a business that’s quite scalable. Within two years, we have a cellar door and we’re selling wine and progressing the business very quickly. I hope we produce something that appeals to people with a sense of adventure,’ he adds.

Ocean influence

The unique underwater vinification process extends well beyond the fact that wine is submerged underwater. The ocean impacts the winemaking process in several ways.

In addition to offering a constant temperature in a pressured environment with a lack of oxygen, the lees are relentlessly stirred by the currents and tides.

‘It’s not unusual to have waves three metres high in Augusta. That equates to the vats turning six times per minute. It’s a washing machine!’ shares Poirmeur. ‘What is really crazy is that we are not controlling anything. That is part of the poetry.’

Wines undergo a double fermentation – somewhat similar to the méthode traditionelle. Except that this happens in a special 300-litre vat weighted to the ocean floor and the end product is not a sparkling wine.

At most there is subtle effervescence.

Land or ocean?

Subsea Estate’s base wines – Semillon and Shiraz – undergo a first fermentation in stainless steel tanks.

A percentage of this base wine continued its winemaking journey on land in traditional style production. This included ageing in tank for the Semillon and ageing in 30% old oak for the Shiraz.

The remaining base wine was transferred to the Winereef; approximately 10 to 11 vats of each variety. This was aged below the waves at a depth of 20m for a minimum of six months.

A kind of liqueur de tirage (a yeast and sugar combo in this instance) is added and the wine undertakes its secondary ferment and tirage. Large oak staves (medium toast) were added to half of the underwater vats, resulting in a varied oak influence.

The result? Subsea’s Pure Ocean wines are blended 100% from the ocean vats; while its Land & Ocean wines are a minimum of 35% ocean wine and 60% of land-matured wine.

Unlike traditional winemaking, there’s no checking on progress once the vats are underwater.

‘That’s it. There’s no ability to sample from the vats, so it’s a gamble every immersion,’ says Poirmeur.

Varietal selection

For the first Subsea releases, Semillon and Shiraz from vineyards in the Karridale sub-region were purchased from local wineries as bulk wines.

Poirmeur had previously been disappointed with Semillon in his Winereef experiments in France, but he was pleasantly surprised by the Margaret River result.

‘You can’t be too confident on paper, you need to test and make your own opinion,’ he adds.

It’s interesting to note that while Shiraz and Semillon grow very well in Margaret River, the region is better known for its Chardonnay and Cabernet Sauvignon.

Although plenty of wineries produce Shiraz, the cooler southern vineyards are particularly prized for aromatics and fruit quality.

Very few single-varietal Semillons are still made in the region, which is a shame as they can be exceptional. Most producers instead use the grape in Bordeaux white blends.

I suspect Semillon and Shiraz were chosen for this project as the grapes are more affordable than Margaret River icons Chardonnay and Cabernet – especially as these first wines from the 2023 and 2024 vintages are a trial.

Grand designs

In addition to each vintage of wine, there is the date of immersion. The release I tasted is from the 2024 first immersion.

Poirmeur adds: ‘We refilled the vats directly after the first immersion. We will have another 15,000 bottles produced in June from this: half Semillon, half Shiraz.’

Production is set to increase in future. ‘As we build the brand and get traction with sales opportunities, we will increase scale with additional vats, and add other varieties and styles to our range,’ says Poirmeur.

Adams says the future could include grapes from further afield. ‘It could even be Frankland River – it depends on the grapes and the wine that we are using in the process. The fantastic thing about Western Australia is we do have access to great quality fruit and great quality wine for the process.’

The pair are keen to point out that the first four wines are just the beginning.

‘Right now, these are a trial. We’ve been going 13 to 14 weeks and we’re only just establishing distribution,’ says Poirmeur.

Taste test

Now, down to the big question: how do the wines taste? For comparison I tasted them alongside bottles from land-based wineries, choosing the same variety, region and vintage where possible.

There’s no question that the process creates unique wines with some very desirable qualities. The most noticeable result from the process is seen in the Pure Ocean wines, with an obvious influence from the lack of oxygen and increased lees stirring.

The company tagline, ‘wine, stirred by nature’, is apt. No winemaker can stir their wines six times a minute on an ongoing basis.

The result of this process is that the Pure Ocean Shiraz has exceptionally fine and soft tannins, closer in character to that of an aged wine. The nose lacked a freshness of fruit; instead, there are meatier notes as a result of reduction (lack of oxygen) during the winemaking process.

The result of limited oxygen and increased lees stirring in the Pure Ocean Semillon is an immensely grassy and herbaceous aroma, with phenolics that are rather more splayed than the Land & Ocean iteration.

The Land & Ocean blends provide a snapshot of the unique characteristics of the Pure Ocean wines, yet with the balance of the qualities of the traditionally made wines.

The verdict

It seems that wine can be made in and to a degree by the ocean. But only partially.

Let’s not kid ourselves that there is a huge amount of human choice and effort involved in the production of these wines – as is there for all wines, including those producers that tout their wine as ‘made in the vineyard’.

Wine is the product of a series of human choices. It would not exist in the natural world without our intervention.

For Subsea wines, there is little reference to the growing process and initial winemaking on land, but these both play a huge role in the final product.

Educated wine enthusiasts might prefer to have the complete process from vine to bottle as transparent as the bottles themselves. However, let’s remember that the majority of drinkers simply want to enjoy a bottle of wine.

Wine is meant to be enjoyed – a fact all too often overlooked. Most wine lovers want to share the story with the people they open it with, and they want to drink something that tastes good.

Subsea’s first release offers both of these in waves – three metres high, to be exact.

Subsea Estate wines: Tasted and rated alongside their ‘landlubber’ counterparts

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