Lessons in wine: Your plonk smells off? Don't blame the cork

Paul Hammond
Follow Paul
Corked wine is a villain blamed for all crimes.

"This wine is corked" is a statement I hear a lot, used pejoratively to describe any wine with a fault. It’s usually an unfounded accusation. There are several innocent non-faults that are considered signs of corkage, including:

• Cloudy wine, generally found in mature wine once sediment has been disrupted.

• Bubbles in red wines, which is usually CO2 added to maintain freshness.

• Actual cork in a wine, caused mostly by a crumbling cork.

None of these are anything to worry about, so drink on.

The term “corked” should only be used to describe wine contaminated with cork taint. It is caused by a chemical called TCA (2,4,6 - trichloroanisole). TCA is formed when the natural fungi which resides in cork comes into contact with chlorides which can be found in bleaches and sterilisation products in wineries. Since the 1990s most wineries have eradicated the use of these cleaning products, greatly reducing instances of corked wine. However, until the early 2000s it was estimated 10 per cent of wine was corked and the problem hasn’t been completely solved even today.

Corked wine isn’t harmful, just unpleasant to smell and taste. A corked wine will smell of damp, wet cardboard and ironically smell like a dusty wine cellar. The chemical TCA will also mask the smell of fruit and shorten the taste. If any of these characteristics are apparent in a wine you should ask for it to be replaced, although the potency of the corked smell can vary considerably.

Aside from being corked, there are plenty of other defects that can ruin a wine. The most common is a wine that’s “oxidised”, something that’s caused by the bottle absorbing too much oxygen. Micro-oxygenation is good for wine and helps it age, an advantage of cork over screwcap, which allows no oxygen into the bottle. But too much oxygen causes a lack of freshness, creating a sherry fino-like smell in whites and bitter-sweet flavours in reds. More than anything else, the wine will become flat and stale. When you encounter this, you should say the wine is oxidised, not corked; you can still ask for it to be replaced.

To help prevent oxidisation, store your wine in a bonded warehouse or temperature controlled fridge or cellar; this will greatly reduce the risk of ending up with a bad bottle.

Other problems include volatile acids, causing a wine to smell of acetic acid (or vinegar or nail polish or glue), caused by ethyl acetate. There is also the build-up of too much SO2 (sulphur dioxide), which is used to protect wine from oxygen. If present in abundance, it will make the wine smell of a newly struck match. Finally, if a wine smells of rotten eggs or burning rubber, it’s been contaminated with H2S (hydrogen sulphide). This terrible odour can also smell of garlic or even sewage.

Corked wine is a villain blamed for all crimes. Quote the above and bamboozle your friends (and even some sommeliers) with your knowledge. Then send the bottle back.


City A.M. Wine Club - Whether you’re an investor or an oenophile, joining City A.M.’s wine club can help you build your perfect cellar. Find out more here.

City A.M.'s opinion pages are a place for thought-provoking views and debate. These views are not necessarily shared by City A.M.

Related articles