"Wine can only be made from grapes and yeasts, without any additives or preservatives," says Moldovan winemaker Vitalie Popa. This is what his "auric infinity barrel" is supposed to make possible - the reinvention of the wine barrel. Alexander Lupersböck spoke to him.
"Winemaking Game Changer" is written on the transparent bottoms of the "auric infinity barrels". Vitalie Popa, a winemaker from the Republic of Moldova, has scrutinised the basic structure of wine barrels that have remained unchanged for centuries. His new design is a wooden wine barrel that is airtight and without any oxygen or additives or preservatives, enabling vinification from the mash to the finished wine. This could revolutionise the winemaking trade. His "isobaric vinification in wooden barrels" should save professionals a lot of work and also make it possible for micro and hobby winemakers to produce wine without any cellar equipment.
In 2021, Popa approached barrel manufacturer Alexander Gantenbrink, who had founded the company "auric barrels" in Croatia in 2016, with his invention. Together, they built prototypes of the barrel called "auric infinity", the suitability of which was confirmed in extensive tests at Hochschule Geisenheim University in 2021 and 2022. Sales will start in spring 2024.
Popa, who has a decade and a half of international experience, identified three major problems with ageing in conventional wooden barrels: Oxidation, impurities and evaporation. "Wineries spend a lot of money to solve these three problems. They have to control the temperature and humidity in the cellar, and they use additives and sulphur to minimise oxidation," says Popa, "my aim was to make wine without any additives, because the grape itself has everything you need."
The silicone stopper, which is usually used for wooden barrels today, is opened for three purposes: To take laboratory samples, to draw samples and to fill the barrels. However, each opening can lead to oxidation, contamination and evaporation. The wines in conventional barrels are thus exposed to constant macro-oxidation: Through the leaking silicone stopper, the gaps between the barrel staves and changing air pressure due to fluctuating temperatures and humidity in the cellars. They must therefore be stabilised with sulphur.
Popa was the first to design a new type of stainless steel stopper ("V-Bung") that seals the barrel airtight. This allows samples to be taken under pressure without oxygen ingress using a permanently integrated, flexible probe. He also noticed that conventional barrels no longer remained tight under increased internal pressure. So he installed silicone seals between the individual barrel staves and replaced the conventional six barrel tyres with rivets with eight adjustable tyres with bolts, which exert the same force regardless of the position on the barrel.
As the gas molecules are smaller than the pores in the structure of the wood, they can penetrate the wood, which leads to a loss of pressure in the empty barrel, reports Vitalie Popa. As soon as the barrel is filled with liquid and is pressurised by the carbon dioxide from fermentation or by added nitrogen, the pores in the wood close because their molecules are larger. "In an Infinity barrel filled with wine, the pressure remains constant because the wine seals the barrel," explains the inventor, "so I can carry out maceration, fermentation, malolactic fermentation and maturation under uniform pressure conditions, i.e. isobaric, in a wooden barrel. No one has ever tried this before." The "auric infinity barrel" is already patented and was honoured with the Innovation Award at Vinitech Sifel 2022 in Bordeaux.
"We tested the technology with different pressure values from 0.3 bar to 1.5 bar in 225-litre barrels. However, the pressure in the Infinity barrels must not be higher than 0.5 bar. The excess pressure can escape through a valve in the V-bung," explains Alexander Gantenbrink. "We voluntarily comply with the pressurised container regulation because nothing has yet been defined in this regard for wooden barrels. However, we are currently carrying out a risk analysis together with TÜV in order to obtain the relevant certificate."
The barrels are fitted with a transparent disc on one side of the base. Popa: "The University of Geisenheim has discovered that fermentation works better when sunlight is added. Yeasts, bacteria and enzymes are found on the grapes and are known to be active in hot and cold weather as well as in sunlight. I am convinced that yeasts use the sun as a source of energy. Their metabolism is different because they don't have to concentrate 100 per cent on converting sugar into alcohol in order to obtain energy. It's more like this: aren't we putting the yeasts under unnecessary stress if we let them work in complete darkness? I am also sure that yeasts that have received sunlight during fermentation are more stable and longer-lasting." However, this still needs to be scientifically proven.
The most important difference to conventional barrels, however, is the very low amount of oxygen in the wines during vinification and storage. "We can work with real micro-oxidation instead of macro-oxidation. In conventional winemaking, the wines have to be stabilised. We guarantee that wines made with our technology are much more durable - and without additives and preservatives such as sulphur," says Popa.
The dissolved oxygen content was measured during the trials. During maceration, fermentation, malolactic fermentation and maturation, this varied between 0.07 and 0.135 milligrams per litre. "No other study has ever come close to these micro-oxygen levels in wooden barrels. We also have data proving that increasing the cellar temperature reduces the dissolved oxygen content and oxidation in the wine, which is the opposite of conventional winemaking and barrel ageing. This gives every winemaker the opportunity to make wines exclusively from grapes and naturally occurring yeasts, regardless of whether they are natural or conventional winemakers," says Vitalie Popa. He emphasises one aspect in particular: "During tastings immediately after fermentation in Geisenheim, our wines were estimated by the tasters to have matured for three to six months. This means that they no longer need to be stored and can be drunk immediately. That saves time and money."
The wines have been described by tasters as "different" but fascinatingly fresh, says Popa. The wood flavour was also so well integrated in new barrels that it was barely noticeable. This means that the wine is influenced by the type and origin of the wood, but with different effects. While the flavonoids of the grapes and the wood oxidised in conventional barrels, they remained unaffected in "auric infinity", which led to a more mature mouthfeel. Popa sees another opportunity: "Every sparkling wine produced using the traditional method undergoes a second fermentation anaerobically in the bottle. But what quality could we achieve if we do the first fermentation anaerobically in the Infinity barrel and then bottle the wine completely anaerobically for the second fermentation, without any additives? This could open up new dimensions of flavour - even for sparkling wines that have previously undergone second fermentation exclusively in steel tanks."
Popa summarises the advantages of his invention as follows: "With 'auric infinity', anyone can make wine purely from grapes and yeasts without sacrificing organoleptic and microbiological quality," he says. "As soon as the grapes or the must are filled into our barrels and the V-bung is closed, everything runs by itself. We have real micro-oxidation as well as pressure and temperature, which are extremely important parameters in fermentation, and a transparent barrel bottom for the yeasts. We don't need any sulphur or additives, because the yeasts produce enough sulphur dioxide for the fermentation to run smoothly, as we have proven," says Popa. This allows the winegrowers to concentrate fully on the quality of the grapes. The more naturally the grapes are cultivated, the better the advantages of the "auric infinity" technology can be utilised.
Alexander Gantenbrink lists further points: "The full barrels can be transported without any problems because the wines are so stable. Empty barrels can be filled with nitrogen or CO2 without having to sulphurise them." As the barrels no longer need to be filled, moved and cleaned, winemakers save a lot of labour time in the cellar. And this opens up further opportunities: "You no longer need cellar equipment to make wine. You can fill the barrel directly in the vineyard and the wine makes itself. The cost savings are enormous. This is particularly interesting for hobby winemakers or small businesses. A restaurant could buy its house wine in barrels and fill them by the glass. The wine in the barrel remains stable as it does not come into contact with air." Wines made in this way also fulfil the new regulations on the declaration of additives on labels in the simplest possible way: "We can simply write 'grapes' on our wines and save ourselves the QR code and the website behind it." And he invites: "Anyone can come to us in Croatia, take a look and taste the wines." He has a special offer for quick decision-makers: he is offering the first 2,000 "auric infinity barrels" at an introductory price of 2,000 euros. The sales launch is on 1 May 2024, which may be the start of a revolution in wooden barrels.