Cork taint is most commonly caused by trichloroanisole (TCA), pictured at left. This is a contaminant found in a percentage of natural cork. (It also commonly contaminates fruits and vegetables.) At higher levels, TCA can make a wine smell lightly, or strongly, like a moldy basement, ruining the experience. At lower levels, TCA mutes aromas and flavors, substantially decreasing enjoyment even when one is not necessarily aware of its presence.
In my experience tasting wines for review both here and when I was a contributing editor at Wine Enthusiast from 2013 to 2022, between 3-6% of wines I have tasted that were closed by natural cork showed signs of TCA taint or some other moldy contaminant. These findings are largely consistent with those from the Cork Quality Council, which found an average of 3% of corks contaminated through September 2021 using GCMS testing (numbers were higher in some previous years). As of Q1 2023, the group reports seeing an average of 1%.
Below is a summary of articles I’ve written about cork taint, ordered roughly by overall utility.
Everything you ever wanted to know about cork taint (2020)
Why you should smell the cork when opening a bottle of wine (2018)
How big of an issue is cork taint really? (2022)
How much cork taint comes from sources other than the cork? (2023)
An example of why smelling the cork matters (2020)
How to return a corked bottle of wine (and why you should) (2012)
My Top 10 All-Time Cork Taint Stories: Numbers 10-6 (2022)
My Top 10 All-Time Cork Taint Stories: Numbers 5-1 (2022)
The closure industry is changing (2021)
Yes, cork taint is still a problem (2018)
Eight takeaways on closure choice and cork taint in Washington wine (2019)
On closure choice and cork taint in Washington wine (2018)
The Corked Counter: Numbers from a half year of counting (2011)
How two wines changed the way that I think about cork taint (2013)
Screw it! (or how I came to believe in screw caps and other alternative wine closures) (2010)
Screw it! Part II: The experience of six Washington wineries using alternative closures (2010)
Screw it! Part III: The Closing Argument on Alternative Closures (2010)
Updated May 17, 2023.