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Where the 1-in-10 figure came from isn't certain, but most people agree it's not accurate.

Mike Pomranz
September 22, 2017

If a wine is corked, it's a serious issue. Once cork taint causes a wine to be contaminated with the unwanted compound TCA, it can leave the entire bottle drinking like the liquid was wrung out of old cardboard. Corked bottles are prevalent enough that it's one of the primary reasons restaurants let you taste a bottle before pouring it: Unlike other potential issues like improper storage, whether or not a bottle becomes corked is out of the restaurant's control. But just how prevalent is this phenomenon? The truth is, nobody knows—but the cork industry insists it's not as high as some people suggest.

One common figure that gets tossed around is that about one in every ten bottles is corked. Most anecdotal evidence shows this not to be the case. However, other factors might explain why someone would use this probably-overzealous percentage: Keeping the number high helps raise awareness of cork taint, an issue wine drinkers might not be familiar with. For wineries, if an uneducated customer gets a corked bottle, that customer may simply think it's bad wine and not buy it again, so awareness is key.

But needless to say, for the cork industry, if 10 percent of bottles really did suffer from TCA issues, it wouldn't be good for business, especially as alternative sealing methods like screwcaps become more prevalent. So in a recent discussion with The Drinks Business, Patrick Spencer, executive director of the Cork Forest Conservation Alliance, struck back at the one-in-ten stat.

"The figure that people quote about one in ten wines bottled under cork having cork taint is a fallacy—there is no evidence to back this up—it's a myth that has never been proved," Spencer stated. "Cork used to be a culprit of TCA, but to say that it's the only way it gets into a wine today is fundamentally wrong. You can find TCA in winery walls, floors, hoses and barrels…. We've contacted all of the major wineries in the US asking them to send us their distributor bill backs that show that one in 10 of their wines is tainted and none of them have done because the number isn't that high. Christian Butzke, a professor of oenology in the department of food science at Purdue University did a test where he opened 1,000 bottles of wine under cork and less than 1 percent of them had cork taint."

So where did that one-in-ten figure come from, The Drinks Business asked. "Where do vampires and unicorns come from?" replied Spencer. "Someone made it up."

Obviously, we know how the cork industry feels. But seriously, can no one really tell us how prevalent corked wines are? Well, back in 2009, our own Executive Wine Editor Ray Isle wrote, "The cork industry finds that TCA contaminates a very small number of corks, less than one percent (improved quality controls have helped in recent years). But winemakers tend to find the prevalence to be much higher, from three to five percent. What no one disagrees on is that some percentage of corks are tainted." For wine drinkers, that last point is all that really matters: As long as you know cork taint exists and how to recognize it, you'll be covered.

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