Malu Lambert: Can cork taint be eradicated for ever?

By , 9 May 2022



It’s not all high tech. Palates are employed in the lab to taste wines under different cork samples.

The Funeral for the Cork was held in New York City on 2 October, 2002. A sombrely irreverent affair, four pallbearers wearing suits carried a steel casket through a railway terminal and up to a grand high-ceilinged bar. They placed the casket in front of a stone fireplace, and opened it. The corpse inside was Thierry Bouchon, a figure made from corks. The name, a play on the French word for corkscrew. The funeral was organised by chief pallbearer and confirmed iconoclast Randall Graham, founder and winemaker of Bonny Doon Vineyard in California.

He welcomed the gathered wine cognoscenti to “this heartfelt wake for the old stinker”. Jancis Robinson MW gave a eulogy paying tribute to cork’s many excellent qualities as a way to seal a bottle, concluding: “You’ve had a jolly good run, Monsieur Bouchon. The great big supertanker SS Screwcap has set sail, and there will be no turning back.” The stunt was followed by a dinner abundantly paired with Bonny Doon’s screw cap-sealed wines. Following this, Wine Spectator gamely featured a tombstone with the epitaph “M. Thierry Bouchon (1585–2002) known to his close friends as Corky had died after a long illness with toxin 2,4,6-trichloroanisole implicated in his demise”.

Ringing the death knell was the rise of alternative closures, coming to prominence in a bid to combat ‘cork taint’; the fault at the time seemed to be occuring exponentially in bottles across the world. The doomsday predictions for cork piled up, its demise – and the corkscrew as collateral damage – seemed certain.

The battle for cork was on. Corticeira Amorim, the world’s largest cork processing group, has sales in the region of €800 million annually, with numerous going concerns in five continents. Founded in 1870, the Portuguese company had sat comfortably in their bottle-stopper throne for generations, easily controlling the monopoly of cork production and thereby the closure market.

“We had to change things, otherwise it was dying industry,” remarked marketing director, Carlos de Jesus. This missive was delivered over lunch at Casa Natal do Comendador, the 18th century family manor house that sits squarely amid one of the production facilities just outside of Porto; the old rubbing against the new, like so much in Portugal does. We had spent the morning wandering around the newish technologies’ departments: innovations that are being deployed to the tune of billions of Euros, developed by some of Europe’s most sought-after scientific minds. Huge investment has gone into these various arms in a bid for the eradication of what ended poor old Monsieur Bouchon: toxin 2,4,6-trichloroanisole, or what it is more colloquially known as ‘TCA’. This is a fight they plan to win.

The term ‘corked’ is a misnomer de Jesus underscored. Say a wine is corked in front of any Amorim acolyte and you’ll see a visible shudder. They’re not wrong, it’s not the cork that produces that musty unpleasant character; rather it’s a volatile compound born of the unholy trinity of plant phenols (wood), chlorine and fungi, and it can likewise infest barrels, pallets, cardboard (and spread from any of these)… though its residence of choice unfortunately is cork bark’s accommodating, flexible cells.

The gauntlet thrown down from the wine world’s luminaries was backed by a growing consumer resistance – who wants to be disappointed when opening something special at the table? Amorim has risen to the challenge; work began in 2016, and in 2021 they launched Naturity and Xpür, technologies designed to remove detectable TCA from natural corks as well as to create a new segment of micro-agglomerated stoppers, these sciences were augmented by ‘Non Detectable Technology’ called NDtech, which is a quality screening system that uses gas-chromatographs. Unbelievably precise, individual corks are assessed at an industrial scale and those with more than 0.5 nanograms of TCA per litre are rejected.

With the smell of cork dust in the air, the screech of grinding machines and the constant hum of robotic arms in motion, I was shown about the factory floors. All elements and levels (the different quality categories of natural, champagne as well as conglomerate) of cork production seemed well oiled and in perpetuity, as discs and cylinders were variously spat out or mulch churned. A couple million corks are produced every day in these factories, with an average of 13 billion units per year.

In contrast to the mechanised din, in another wing were the super-quiet Naturity machines, lined up like space pods in stasis. This project is in conjunction with the NOVA School of Science and Technology is employed for whole natural corks. It works, in layman’s terms, by steam cleaning (geekier description: thermal desorption through the use of pressure, temperature, purified water and time). The method is able to extract over 150 volatile compounds, including TCA, resulting in a cleaner cork all round.

For the micro-agglomerated stoppers we came to the Xpür machines. So secretive is the technology that I was only allowed to take photos from a certain angle of the long, submarine-like cylinders with heavily latched doors. They work by cleaning granulated cork while preserving the intrinsics of the cork itself. To do this, De Jesus explains that these machines are able to go ‘supercritical’ – essentially creating another state of matter; not a solid, liquid, gas or plasma, something else entirely that purges the TCA right out of the cork with a supercritical ‘fluid’.

Back at lunch, steaming bacalhau being heaped onto my plate by a butler in full regalia, the conversation had turned more positive from the earlier anecdotes of cork cadavers. Their mission, stated De Jesus, is to “eradicate TCA taint forever”, at least with any Amorim branded products, a promise they are by and large fulfilling with these new, innovative technologies. The numbers rapidly on the uptick support this statement, as of 2021 sales increased by 13% to more than €830 million per annum. De Jesus acknowledged that the never-ending thirst for Prosecco is also helping with this, bringing in new consumers with a product that is traditionally sealed with a cork.

“Cork is also greener than alternative closures,” he emphasised. “Not only do the cork oaks regenerate the bark needed every nine years, with no need for chopping the tree down; natural cork is also sustainable in that it is biodegradable and has generally been found to leave a smaller carbon footprint than screwcaps or plastic toppers.”

However, that’s not to say that TCA taint can’t still infect these corks, once they leave the factory doors it’s open season… the volatile compound could be lurking in a cellar, bottling plant, or pallet near you.

But let’s just say that with the old stinker (that’s TCA, not cork) mostly dealt with, the only question that I have left to ask – in the time-worn screw cap vs. cork debate – is a question of style. The latter allows micro amounts of oxygen into the wine, aiding in its evolution, while the other is anaerobic making it ideal for preservation. So, subjectively, the battle rages on – what do you prefer?

  • Malu Lambert is a freelance food and wine journalist who has written for numerous local and international titles. She is a WSET Diploma student and won the title of Louis Roederer Emerging Wine Writer of the Year 2019. She also owns story-telling agency, Fable, which works with high-end food, wine and hospitality brands, telling their unique stories in a variety of digital formats. Follow her on Twitter: @MaluLambert


5 comment(s)

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    Paul Vandenberg | 11 May 2022

    Amorim is a very wealthy company owned by Portugal’s wealthiest family.
    They spend millions on greenwash.
    They claim to have “guaranteed “ TCA stoppers. The guarantee is worthless.
    I went wood free in 1992 at Worden winery. I talked Randall into a black plastic stopper because I wanted to get away from ugly fake wood and capsules. I needed someone to create demand that I could ride coattails.
    I said in ‘92 that plastic stoppers were just a way station to get to the better solution. ROPP closures.
    Now, is there any one out there that wants to cut bottle weight by 50%? It’s my next goal, 300 gram bottles.
    Paul Vandenberg
    Paradisos del Sol Winery and Organic Vineyard

    Bruce Felix | 10 May 2022

    TCA has been dead for 20 years. Just use DIAM

    Leonardo Ricardez | 10 May 2022

    Completely agree with Kwispedoor, and I’d just like to re iterate that screw caps do allow a very small amount of Oxygen ingress into the wine, in a more controled and stable rate than cork. Additionally, you don’t get the variability you get with corks as no cork is exactly the same (coming from tree bark), thus no bottle even within the same box is the same to the next one after a couple of years of ageing. Plus you don’t get random oxidation issues due to defective corks.
    I too have tasted winest that have been under screw cap for up to 20 years, and they’ve been amazing.
    As far as the carbon footprint, the cork industry always leaves out the fact that whatever % of bottles are corked or deffective due to cork, go directly to waste; that is the glass, the wine, the energy to produce that wine, etc… and that is never accounted for in the carbon footprint calculation.
    Unfortunately, screw caps are not pretty and consumer acceptance is an issue, but if it’s about what’s best for the wine, definitely screw caps are better than cork.

      Jonathan Snashall | 12 May 2022

      You can select liners that allow nominal gas exchange – or ones that don’t.
      Cant see TCA being eradicated in whole cork – its a tiny potent organic molecule already present in the bark of living cork trees – perhaps when we gain control at molecular level – just before the world ends;-0
      DIAM is the way to go if you want to use cork – or gas chromatography of each cork to check for TCA , otherwise its a lottery.

    Kwispedoor | 9 May 2022

    Hi, Malu

    Screwcaps are not really anaerobic (, though I’d agree that they are ideal for preservation. I’ve had many old wines under screwcap by now and they were all pristine so far, bar none.

    It remains curious to me how many people say they prefer screwcap on wines that’s meant to be consumed young and cork on wines meant to be matured. I can understand why producers would say that – because they have to be cognisant of consumer perceptions/preferences – but why consumers would say that seems to me to be more a question of misguided romanticism than practical logic. I’d be more happy with cork on wines meant to be consumed young and screwcap on wines meant to be aged. Let me explain why.

    Cork closures on wines meant to be consumed young arguably offers faster evolution and less chance of reduction issues. Extracting a young cork is also much easier than extracting old corks that often present issues due to over-saturated sogginess or brittle dryness. Furthermore, it’s much easier to get a current vintage wine replaced if it’s affected by TCA (or RBO – let’s keep in mind that TCA and TBA is not cork’s only challenge, not that srewcap wines are totally immune to possible RBO issues either).

    Screwcap closures on wines meant to be matured, means that reduction mostly becomes a non-issue and unscrewing an old wine’s cork can be successfully done by a primary school kid. Preservation is more solid and dependable, with less bottle variation and the risks of TCA and RBO are also greatly reduced. So the sticky scenario of trying to get a decade old Chardonnay that was ruined by TCA replaced with the same vintage, is not such a likely one anymore.

    I’ve had two wines within the last week that were badly affected by strong TCA, a 2008 Pinot Noir and a 2017 Cabernet Sauvignon. Both high-end wines. I can try and get the 2017 Cab replaced, but it’ll cost me time and effort. The 2008 Pinot is just a dead loss. I think I’d have preferred screwcap on both of those…

    Something of note is the advent of Diam/agglomerated cork. I presented a tasting on Friday that required four bottles of each wine. We tasted eight red wines blind (showing different red cultivars to people mostly fairly new to learning about wine). Out of the eight, two had screwcap closures (TSW Cinsault and Raats Dolomite Cabernet Franc), two had natural cork (Villiera Munro Merlot and a Stellenbosch Cabernet – one of the four bottles of the latter wine had TCA) and the other four all had agglomerated cork. This latter group were all priced between R170 and R350 per bottle and were all very good wines. It seems that many winemakers are still both wary of the dangers of cork and wary of the level of consumer acceptance of screwcap.

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