109. Cork Taint Explained - What Corked Wine Actually Means and How to Identify It

Host: Joanne Close Episode Length: 13 minutes 12 seconds Release Date: April 30, 2025

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Episode Description

Cork taint is one of those wine faults that everyone has heard of but very few people can confidently identify. In this episode Joanne finally tackles a topic she has been putting off covering, and it turns out to be one of the most practically useful episodes she has recorded. Whether you are a WSET student who needs to know this for your exam or simply someone who wants to know what to do when a bottle does not smell right, this episode gives you everything you need.

Joanne starts by clearing up the most common misconception, which is the difference between a wine that has bits of cork floating in it and a wine that is genuinely corked. From there she walks through the chemistry of TCA, what it smells like, why some people detect it more easily than others, and exactly what to do if you suspect you have a bad bottle. She also covers where TCA comes from, why it is not just a cork problem, and what the wine industry has done over the past few decades to reduce its occurrence.

This is also one of those episodes where Joanne's practical storytelling is at its best. You will hear about her parents' kitchen cabinet, baby carrots cleaned with bleach, a winery that lost an entire vat of wine to TCA contamination, and a surprisingly useful tip about what to do with a corked bottle if you cannot return it.

What You'll Learn in This Episode What Corked Actually Means

• The difference between bits of cork in your glass and a wine that is genuinely corked
• Why finding cork fragments in your wine does not affect the taste and what to do about it
• Why the term corked refers specifically to TCA contamination and nothing else

Understanding TCA

• What TCA stands for and why we use the abbreviation
• How TCA is described in the WSET textbook and why you need to know it for your exam
• The key aromas associated with TCA - wet cardboard, damp basement, wet dog, mouldy newspaper, and autumnal notes
• Why the amount of TCA in a wine can vary from obvious to extremely subtle
• Why a subtly corked wine can be particularly damaging because it dulls fruit aromas without being immediately obvious
• Why some people detect cork taint more easily than others and why this is completely normal

How Sensitive Is Your Nose

• Why the detection threshold for TCA is measured in parts per trillion
• How to put that sensitivity into context - one second in 32,000 years, or a few drops in an Olympic swimming pool
• Why CO2 in sparkling wines makes TCA easier to detect

Where TCA Comes From

• Why TCA needs phenols plus chlorine to form
• Why natural cork is the most common source but not the only one
• How wood pallets, barrels, and even the architecture of a winery can harbour TCA
• Why wineries avoid bleach-based cleaning products
• The banned chlorophenol fungicide once used on cork trees and why its residues are still causing problems decades later
• Why TCA is not limited to wine, with examples from carrots and kitchen cabinets

What to Do with a Corked Bottle

• Why leaving the wine in the glass for a while will make the fault more obvious rather than less
• Whether you can cook with a corked wine and what David Bird says about it
• How to return a corked bottle to the retailer and what happens next in the supply chain
• How to find a corked bottle to smell for reference at your local wine shop
• Why a corked bottle in a case does not mean the whole case is affected

Episode Highlights and Quotes

"If the wine doesn't taste like it did last time, it can just dampen or dull the fruit aromas and flavors just a little bit. And I think this can be perhaps sometimes the most damaging to a wine."

"The threshold is in parts per trillion. To put this into perspective, it is like one second in 32,000 years, or a few drops in an Olympic size swimming pool."

"If you're in a setting and you feel the wine may be corked, you say hey, this wine, I'm not sure, could you smell it as well. It is a dialogue. We are not going to do that to each other."

Cork Taint Quick Reference Guide What Corked Smells Like

Wet cardboard Damp basement Wet dog Mouldy newspaper Autumnal notes (David Bird's description)

What Causes TCA

Chlorine reacting with wood materials, converted by microbes into TCA Most commonly associated with natural cork Also found in wood pallets, barrels, winery architecture, and cardboard packaging

Key Facts for WSET Students

TCA stands for 2,4,6-trichloroanisole Detection threshold measured in parts per trillion More easily detected in sparkling wines due to CO2 Incidence of cork taint has reduced significantly since the 1990s as cork companies have worked to address the issue Still occurs and worth knowing how to identify

What to Do with a Corked Bottle

Leave it in the glass for 30 minutes and revisit - the fault will become more obvious with air exposure Return it to the retailer for a credit Ask your local wine shop if they have a corked bottle you can smell for reference

Resources Mentioned

Understanding Wine Technology by David Bird - recommended for clear explanations of wine chemistry written accessibly for non-scientists

Coming Up Next

Joanne asked newsletter subscribers to vote on the summer podcast direction. Options included wine faults, true wine crime, natural wine including pet nat, orange wines, and biodynamics, or something else entirely. Results are coming in. Make sure you are on the newsletter to find out where the podcast goes next and to cast your vote at https://mailchi.mp/6648859973ba/newsletter

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About Wine Educate

Wine Educate is a WSET Approved Programme Provider offering internationally recognized wine certification courses. Through the podcast, Joanne Close makes wine education accessible to everyone, breaking down complex topics into practical, easy-to-understand lessons. Whether you are studying for your WSET certification or simply want to learn more about wine, you will find the guidance and knowledge you need to enjoy wine with confidence.

Episode 109 of the Wine Educate Podcast | Hosted by Joanne Close | © 2025 Wine Educate