A Discussion of Cork Taint

Scene:  You are at a nice restaurant, one with an amazing wine list and delicious food to match!  Your sommelier or waiter brings out the bottle of wine you have carefully chosen, he shows you the bottle, uncorks, and pours you a taste.  Your swirl, then take a long sniff - anticipating the aromas.  Instead, you notice something is off.  Is it just not how you thought it would smell?  Will the taste be better?  Or, is something more at play here?  How do you know when your wine isn't just bad, it's B-A-D, as in something is wrong with it.

Image courtesy of My Grape Escape.ie

You may have seen wines referred to as "corked" or having "cork taint".  Cork taint is defined by Ken's Wine Guide (http://www.kenswineguide.com) as referring to a set of undesirable smells or tastes found in a bottle of wine, especially spoilage that can only be detected after bottling, aging and opening. Though modern studies have shown that other factors can also be responsible for taint – including wooden barrels, storage conditions and the transportation of corks and wine – the cork is normally considered to be responsible, and a wine found to be tainted on opening is said to be "corked".  

Cork taint can be caused by 2,4,6-Trichloroanisole, or TCA.  TCA is a chemical that is harmless, yet found everywhere and gives wine a musty flavor at low levels.  TCA most frequently comes from the cork or through the cork, but can also come from airborne molds, contaminated winery or bottling equipment or chlorine-based compounds in wineries or wine cellars.  TCA, however, is not the only cause of spoiled wine.  Several bacteria and molds, as well as oxidation due to plastic stoppers can cause wine to be bad.

Image courtesy of Wikipedia

Interestingly, this issue has caused a divide between cork growers on one side and producers of synthetic or screw top (Stelvin closure) on the other side.  However, Screw caps and synthetic corks can be prone to another aroma taint: sulphidisation, which arises from the reduced oxygen supply which concentrates sulphurous smells arising from universal preservatives.  Heald, Claire, BBC News Magazine (January 17, 2007).

Image courtesy of http://usaherald.com/uncorked-cork-vs-screw-cap-matter/

How do you recognize cork taint?  Wines that are "corked" can smell moldy or musty like cardboard or damp cement or wet newspapers.  At lower levels, TCA can remove a wine's flavors making the wine taste dull.  There are no acceptable levels of TCA in wines.  If multiple vintages of a cellar's wine have this issue, it can be a cellar-wide, or systemic, taint.  Other causes of cork taint include anti-fungal treatments, flame-retardant paints and moldy cellars.  

In the grand scheme of things, taking into account how many bottles of wine are produced and distributed, the percentages and likelihood of cork taint is low.  However, if you are in a restaurant and that is your thoughtfully chosen, expensive bottle of wine, statistics are of no consequence.  If you, or someone in your party feels that your wine has cork taint, the best course of action would be to begin by asking the waiter or sommelier's advice.  Typically, if your server has any wine experience, they will replace the bottle with a new one.  Obviously, it is likely not the restaurant's fault, and, thus, it is best handled in a kind and respectful manner.

Cheers!

Mary Jo