In 2019, something unusual happened. In August of that year, I didn’t open a single bottle of cork tainted wine for review. (Cork taint is a contaminant in wine most commonly caused by trichloroanisole.)
To give a sense of how strange that is, it only happened on two other occasions in the prior four years. In fact, just that June I’d had 10 corked bottles. In September, I only had a single corked bottle. Then I did not have another corked wine for the rest of the entire year.
That means I had one corked bottle over a five-month span while opening hundreds of bottles. That was, to put it mildly, unprecedented.
Overall in 2019, I had 35 cork tainted bottles of wine. That might seem like a lot, but for someone who tastes wine for a living, I assure you that it is not. My numbers for 2019 were actually quite low compared to recent years. For example, the year prior, I had 64 cork tainted bottles, tasting roughly the same number of wines.
August of 2019 seemed to mark a turning point for cork taint. In 2020, I had corked bottles of wine every month except two. However, I had a total of 23 tainted bottles – the lowest number I’ve ever had across a single year. Again, I was tasting roughly the same amount of wine.
Why so fewer corked bottles?
My first thought as to why I was seeing so fewer corked bottles was that perhaps I’d had a large diminution in my sensitivity to the fault. However, I’ve seen no evidence that’s the case, and I continue to detect cork taint at a low level.
My second thought was less frightening and also more compelling. Was I actually witnessing a dramatic decrease in cork taint? In 2015, I had 96 corked bottles of wines in my tastings. Now I was seeing a quarter as many.
I’ve collected data on closure type and cork taint for the wines I taste for review going back to 2016. (In 2015, I have data on the total number of wines and number of corked bottles but not closure type.) I hadn’t rolled up the data for some time, so it seemed like a good time to do so to see what the data said. The answer was quite surprising.
A dramatic increase in alternative closure usage contributed to a decrease in the number of corked wines.
Looking at the data, yes, the overall number of cork tainted wines that I was seeing during my tastings had gone down significantly. However, this was due in part to a large increase in the number of producers using alternative closures that are taint-free that I wrote about recently.
As one would expect, the large decrease in the number of wines closed by natural cork contributed to a dramatic drop in the overall number of corked wines I saw. But that also doesn’t appear to tell the entire story.
Cork taint appears to have gone down slightly.
When looking at the percentage of wines closed by cork, the data are less convincing that cork taint has gone down dramatically. If anything, it appears to have gone down slightly, as the change is only dramatic when compared to some years.
For instance, in 2016, a shocking 6.21% of wines I opened for review showed signs of TCA or some other moldy contaminant. In 2020 that number was 2.78% and in 2021 it was 3.05%, essentially half as much. The 2020 percentage is the lowest number I’ve ever seen, and 2021 is the second lowest.
However, as recently as 2017, 3.59% of the wines I sampled presented as cork tainted, which is in the ballpark of my 2020 and 2021 numbers. We know that, unless some change has occurred, data might vary but eventually regresses to the mean. So some years the numbers will be higher, and we would expect that some years they would be lower.
Is there an actual change happening in cork taint?
Still, it is unequivocally true that 2020 and 2021 were both the lowest number and lowest percentages I’ve ever seen for cork taint. I haven’t done a formal data analysis, but I would assume the differences would be statistically lower than other years given the large sample size.
I will note that the roughly 3% number I saw in 2020 and 2021 is identical to the number that the Cork Quality Council (CQC) reports seeing those years. Looking at the CQC data also gives reason for hope.
In Q1 2022 and Q1 2023, CQC reports 1% of corks with TCA at less than one part per trillion. Given that my numbers have generally tracked well with theirs, I would expect that to start showing up in my tastings last year and to a greater extent this year.
Unfortunately, my 2022 data were lost in a hard-drive crash. Will I see a dramatic decrease in my 2023 numbers from 3% down to 1%? We’ll see when I roll the data up next year.
Why might there be a decrease in cork taint?
To the extent that there is an actual decrease in cork taint, there are several reasons it might be happening. The first is that a number of major cork producers have introduced corks that are individually tested for cork taint using GCMS.
Is this testing perfect? It is not. It is also very expensive and exclusively used on high-end wines. However, it does likely cut down on the percentage of tainted wines, at least for those who pay for the privilege. That might account for some of the reduction I saw in 2020 and 2021.
Perhaps more importantly, in 2021, Amorim, the world’s largest supplier of closures, announced that it had added a step to its production that would eliminate cork taint from all of its corks.
Does this technology work as advertised? That remains to be seen, but the Cork Quality Council data indicate that, at minimum, they saw a dramatic decrease in the percentage of cork tainted wines that coincided with the rollout of that technology.
What’s next for cork taint?
Even if we do see the dramatic decrease in cork taint the that CQC numbers indicates is coming, I would argue that 1% remains an unacceptably high level. This is particularly true when there are closures with a proven track record of success where their TCA contamination rate is zero. The industry needs to continue to work to completely eradicate cork taint. Until it does, it remains an embarrassing blemish on the industry.
Still, when one combines the recent increase in alternative closure use with a decrease in cork taint that the Cork Quality Council data indicates is coming – I’m personally in the trust but verify stage on that – it means that consumers should see a lot fewer cork tainted bottles on wines released now than they did five years ago. That’s something that every wine lover should celebrate.
Will we ever be able to get the percentage of cork tainted wines to zero? It seems hard to imagine as long as wines are closed with natural cork. That said, recent technological improvements seem promising.
Even if the problem of cork taint is eventually solved once and for all, don’t worry. We still won’t be done with cork taint. Anyone who has a wine cellar of any size has plenty of corked bottles in there waiting for them.
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