In a recent article by Sean P. Sullivan he made mention that the unfortunate chemical compound, 2,4,6-trichloroanisole (AKA TCA or colloquially, ‘cork taint’) is in theory, on the outs. Sullivan stated that in his experience with the wines he’s been tasting in recent years, he’s detected it far less than he used to.

It’s always difficult to make any decisive declarations about TCA as it’s something that’s very much dependent upon sensitivity to the fault. Personally, I’m no cork hound and unless it’s quite strong aromatically, I have to confirm that there’s a problem on the palate where I can detect it with relatively ease when it exists.

Despite my seemingly diminished sensitive to this ‘wonderful’ contaminant in wines (that doesn’t always come from natural corks mind you), I have to say that my observations are to the contrary of what Sullivan has found and it appears to me that recently the levels of TCA contamination are massively on the rise in bottles sealed via natural cork.

The golden age of cork

It’s important to note that pre-2020, TCA had become exceedingly rare for me to find in wines from major regions. I say this as someone tasting wines from Southern Europe as well as other regions of the world in various competitions. There would be at most 1% of the wines tasted that would have a TCA or another cork flaw. I say ‘another’ as keep in mind that corks can have issues with oxidation and other random things given that they’re a porous, natural substance.

But the rate of detection can depend a great deal upon the wine region of production as much as the person tasting. It may very well be the case that Sullivan has been finding less issue in wines from Washington state as there are in fact fewer problems in that specific region.

My experience has long shown that wines from ‘secondary’ production markets (those not in the heavy hitters at the top of production such as France, Italy, Spain, and California) would see a higher number of issues. Obviously, no cork producer would ever admit to passing their second-rate corks off to these types of wine regions. The producers however have damned-well noticed that no matter how much they spent, they still had a high rate of contamination/failure and, in covering regions such as Croatia and Georgia, I can confirm this firsthand, both that they’re not skimping on the corks they buy and that the fail contamination rate is unjustly higher than other regions.

I even once heard of a producer in one of these regions buying all his corks from a supplier in California and having them shipped to where he is in Europe, this despite the corks coming from Portugal. The reason for committing to this much shipping waste was that given the exceedingly litigious nature of Americans, the thinking was that the cork provider would be terrified to sell a flawed product in the US.

It’s for this that in a tasting of young Pošip wines from Korčula, Croatia, absolutely all the wines were sealed with the composite, truly sterile corks made by Diam. This was never the case before as everyone used natural corks as an issue of perception (many did and still believe that anything other than natural cork would be seen as ‘cheap’ wine), but I’ve seen this pivot to manufactured corks more and more.

But this is possibly why Sullivan (as well as others) have noticed less issues in corks recently. There have been seemingly less of the lower-end natural corks coming to market and those in the higher-end were being checked very, very thoroughly via gas chromatography and other systems. All of this in turned worked to make cork issues, for the most part, non-issues.

Due to this, I’ve very much been pro-cork on upper-end wines for some time but not to the extent where I’d have entered a ‘discussion’ about it on Twitter.

What happened?

So, everything seemed good and getting better each year when it came to natural cork.

Then the pandemic came and the wines I was initially tasting in spring of 2020, like those for the DOQ Priorat report showed everything to be continuing without issue. But then, once 2021 rolled around and we started seeing the supply chain issues that would plague the wine industry for the next year plus, I started detecting more faults in wines that were issues found from natural corks.

In essence, any wine that’s been bottled with corks that were produced from 2020 onwards have shown the same issues and fail rates of around 5% (or even higher sometimes) that haven’t been seen for nearly a decade. What’s frustrating however is that all this data, while firsthand experience, is anecdotal.

When I was judging at the 2023 Decanter Awards (after an unasked-for, but Covid-granted hiatus of three years), there was a flight of 12 wines and of them, 30% required a replacement bottle be brought. The replacement wine was fine showing that it was not a wine problem, but a cork problem. Half of those deemed faults were TCA issues, thus a 15% fail rate. But, was this simply a small batch of these wines that had problems for whatever reason or could larger conclusions be drawn? We can never know.

Even in the small line of experimental wines I produce, I’ve had wines pop up with blatant TCA issues which is ridiculous as I bought what were supposed ‘top-end’ corks. Much like the Croatians I’ll probably switch to Diam in the future as when you’re producing only a couple of hundred bottles of a wine, even one having faults is untenable.

I can only guess that there are two issues at stake here. The first is that it’s been difficult for cork producers to maintain quality levels due to the pandemic. Staffing has constantly been an issue for everyone the world over and surely it must have affected them as well, although this is purely theoretical.

The other and much scarier issue is that we’re seeing the initial results of Climate Change for the cork industry in that the Iberian Peninsula (where most of the wine world’s corks are produced) is in the middle of a massive drought. This does affect cork production although it’s mainly been proven to slow the growth of cork, something that takes 25-30 years before it can be harvested. But it can easily be the case that it’s changing the make up and consistency of corks as well. We’re too early in what is a long game industry to have any solid answers on this, but like everything with a potential link to Climate Change issues (which, is essentially everything on the planet) this needs to be taken into consideration now.

A cork is a cork

Given all the issues and the fact that myself as well as a number of wine judges and winemakers I know in Europe have been seeing more, not less problems with corks currently, why do we still use them?

Well, according to the ‘Associação Portuguesa da Cortiça’, sommeliers prefer corks although the Portuguese Cork Association is the absolute antithesis of impartial.

Again, go and muck about Twitter (oh, sorry, ‘X’) if you want to see the passion around corks and why there is a core group of people who will always prefer them. I fully admit that the pulling of a cork as opposed to the cracking of a screwcap is a great deal more fulfilling, but we’ve clearly been conditioned to feel this way.

There are now a great many substitutes for natural cork with Diam, which is produced up in Roussillon, France, being the leading one. I was initially skeptical of these as they seemed to keep wines a bit closed and you simply can’t use a Coravin with them. But I’ve seen that when managed well they’re a fine alternative and in addition to not having any issues with TCA, the consistency of the material is excellent so you don’t get random oxidation or other issues.

It’s clear that producers even in first-tier countries are taking note of the advantages. Via two dozen wines I tasted just last week from classic regions in France and Spain, I noted that there wasn’t a single natural cork in the lot. They either used Diam, Nomacorc, or screwcap, with the Diam 30 on a bottle of Sauternes being one of the most surprising things to see.

By no means should we ditch natural corks though. In addition to the sentimental attachment, cork forests have great potential for carbon capture, the cork harvest and production is quite low energy, it provides jobs, and if done correctly, it’s a completely sustainable industry.

It’s just that we need to have an honest conversation about the inherent issues of corks and that these seem to be on the rise. If it’s the case that only upper-end wines will be able to use them due to the costs in guaranteeing there is no TCA, then we’ll need to accept that. We’ll also have to accept using Diam or other alternatives for some wines and screwcaps for others.

Like every issue we’re facing as both wine lovers and residents of this planet, we need to investigate hybrid solutions to ensure our collective future. We just need to fess up to the fact that there are in fact problems and they need to be dealt with, immediately.

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