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How to tell if my wine has gone bad?

Follow our guide to detect wine faults

· Wine Culture

Have you ever noticed a weird smell or an odd colorwhen tasting wine? 

This is probably because you’ve met the common defects that wine can have. Some of them can be repaired while some are permanent. Follow the guide! 

Corked wines

If the wine smells like wet cardboard or mould, itis highly possible that the wine is corked. This is caused by a chemical called trichloroanisole (TCA), which comes from a fungus that grows naturally in the cork or in rare cases, in the oak barrels or winery’s infrastructure.

TCA usually spreads from natural corks, and in rare cases found in capped wines too

In some cases, TCA activates and contaminates the wine, leaving a smell of damp or rot. There’s no solution to repair this defect, all you have to do is replace the bottle. 


When a white wine turns orange, or a red wine turns brown, it's probably due to excessive oxidation. Note that old wines would show a similar color, make sure you distinguish them from another. Once a wine is overly oxidized, the fruity aromas would gradually fade away and a vinegar smell starts to appear. 

Some wines are deliberately oxidated (Oloroso sherry, Tawny port...)

Excessive oxidation would mean that the wine has passed its drinkable age or that the storing conditions were not good. This defect cannot be fixed, all you have to do is to open another one! 


Reduction is the opposite of oxidation, and often a result from the lack of oxygen during the winemaking process. In such cases, it makes the wine smell like cabbage or farmland. You may also mix up this defect with corked wines.  

This defect can be fixed. All you need is to pour the wine into a decanter and energetically swirl it to accelerate the oxygenation process and save your wine. 


Brett is often associated to the smell of horse and barnyard

Brettanomyces, shortened to Brett, is an undesirable yeast that grows in the winery. When brett enters in contact with the wine, it could contaminate the wine and ruin its aromatic profile, leaving strong meat smell or the scents of stable.

Unfortunately, there is no solution for this defect. Note that some wineries will have this on purpose in a limited amount so as to enhance the complexity of flavors in wine. 


Ever noticed a fizzy sensation when sipping on a still wine? These tiny bubbles might be the result of an unfinished fermentation which starts again in the bottle, creating CO2. This would be considered a defect.

Some winemakers intentionally inject a tiny amount of CO2 into the wine before bottling to bring a refreshing effect. In both cases, if you don’t like this, use a decanter to let the CO2 dissipate before tasting it again. 


Some people may have misunderstandings on sediment in wine and may see this as a problem. In fact, it’s not a defect and is simply harmless clusters of grape skins and tannins. The sediment usually appears in  old red wines or wines that have not been filtered during their making.

In order to remove the sediment, you need to decant the wine to separate the sediment from the liquid. Pour it into a decanter and leave the sediment in the bottle. 

White crystals?

You may also notice the white crystals in your glass of white wine and may question the quality of the wine. Actually, it’s not a defect. These are usually tartaric acid and potassium that precipitate in cold environment such as in a fridge.

They may also appear as stuck to the cork inside the bottle. Don’t worry, they are totally harmless and do not alter the quality nor the aromas of you wine.

Next time you will taste or smell something unusual in your glass, we hope that this article will help you assess the reason behind it!

Founded in 2018 by Matthieu Ventelon, Hedonia is the first institution in China combining professional Wine and Etiquette expertise in the same training offer.

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