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You don’t want to drink a bad bottle of wine just because you didn’t realize it was off. Being able to spot the faults in your wine is therefore important.

faulty bottle of wine lying of the table

They say, like people, wine is a living product, which is what makes it interesting. But it also has its downside. Here are 4 common wine faults and how to identify them. But remember, a faulty wine from a producer doesn’t mean that all their wines are, or will be forever, faulty. So, don’t stop experimenting.



Oxygen is wine’s frenemy. This is a contamination caused by too much exposure to oxygen. It is similar to what happens when you leave a slice of apple in the open and its color changes to brown. Oxidation is a common fault, generally in older wines, and white wines are more susceptible to it than reds. However, in some wines like Madeira and tawny ports oxidation is deliberate.

How does it happen?

Oxidation can happen if the wine has spent too long in the cellar or it was not sealed and stored properly after opening.


It turns bright red wines to brownish-orange and white wines to dark yellow. Both lack freshness and tastes dull, dry and bitter.

What should you do?

This wine is not toxic but is definitely not pleasant to drink. You can politely ask for a replacement if you are at a restaurant.


Corked (Cork Taint)

A wine is called ‘corked’ when it is contaminated with cork taint caused by the presence of a chemical compound called TCA. Most often TCA is transferred to the wine through a natural cork closure. While high levels of such cork taints are distinctive, lower levels are much harder to spot. It may sometimes be confused with oxidation or other faults.

How does it happen?

TCA does not happen naturally; rather airborne fungi create it. TCA can also be present in tree barks (used to make natural corks), oak barrels, wooden pallets or elsewhere in the winery. If undetected it can ruin not only a bottle but also an entire batch of wines.


Typically smells like rotten cardboard, wet newspaper, old socks, damp cloth or a damp basement. The wines are likely to lack fruitiness and taste dull.

What should you do?

Corked wine is surely not harmful to drink but it’s undrinkable. Best that you send the bottle back, or ditch the wine.

TIP:Cork taint does not happen if a wine bottle has a synthetic cork or a screw cap closure.



This happens when the wine is exposed to too much heat or high temperatures. ‘Cooked’ wines can also show signs of oxidation.

How does it happen?

This can happen anywhere: on its journey from the winery to the shop, when it’s left by a sunny window, in a warm warehouse, on top of an oven, stacked on a shelf with overhead lamps, in the boot of your car during summer.


The cork will be partially sticking out from the bottle (heat causes the liquid to expand) and the fruit flavors in the wine will be baked.

What should you do?

While you can’t fix it, you can definitely prevent by storing the wines in a cool, dark place. Avoid temperature fluctuations and direct exposure to sunlight. 12-18 degrees Celsius is ideal.



Wine can turn sour, or into vinegar if it is not sealed and stored properly for a long time. This is a case of extreme oxidation. While it can also happen during the manufacturing process winemakers largely taken care of it, which is why not all wines taste vinegary.

How does it happen?

Acetic acid, in wine, is made by a particular type of bacteria that can be found everywhere: in the air, on the grapes etc. When the wine is exposed to too much oxygen this bacteria can get into the wine slowly turning the alcohol into acetic acid, which is also associated with the smell and taste of vinegar.


At first, the wine will have a peculiar strong smell and a sour taste. In a few days, it will become sourer and less strong.

What should you do?

Unfortunately, this wine is undrinkable. Consider making wine vinegar out it.

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