A guide to wine faults

There’s nothing worse is there? There you are, wilting under the gaze of a stern looking waiter, as you nose your glass. Your job is simple; is the wine good, or is it in bad nick? So far, so straightforward…

Not so, according to many of us (the ability to accurately spot wine faults is voiced as a common concern in our wine tasting events). How can you make absolutely sure the wine is in bad condition? After all, you’ve had wines you thought were duff, but whether they were faulty or not was another matter.

Many people assume that when a wine is in bad condition it is “corked”. In reality this is just one of a range of possible faults. How, then, do you spot out of condition bottles, and what do you do about it when you find them? Here’s the process (it will help you cover the main bases):

Take a close look

Firstly consider the wine’s appearance.

If you see crystals in the glass

Don’t necessarily worry about these. This is almost never a fault. Crystals are just generally tartrates, which are a natural by-product of the winemaking process. You can crunch these if you like (they taste of nothing).

If you see bits of cork floating in the glass

Likewise, if you see cork floating around in the wine, this is not a sign of corked wine, or what wine buffs occasionally term “cork taint”. It’s just a sign of a pourer/bottle opener who’s a) not very observant or b) a little clumsy.

If you are seeing bubbles in a non sparkling wine

In white wine this is also not necessarily the sign of a fault. Certain winemakers (particularly the Germans and Italians) may leave carbon dioxide (another by-product of fermentation) in the wine to give it a little added “spritz”.

If you are seeing bubbles in a red wine, unless it’s a sparkling example (there are a number of red sparklers out there), it could be a sign that the wine is refermenting, which is a problem.

If the wine is hazy or cloudy

This, generally, is bad news. A hazy or cloudy appearance is a sign that the wine is unstable, and should be treated with caution.

Then have a sniff

Swirl the wine in the glass to release the aromas. A host of tasting terms are used to describe wine that is in poor condition, cleverly represented in Jean Lenoir’s wine fault aroma phial kit available from Amazon here, an interactive product we use regularly in our events (and a highly recommended tool).

Otherwise, key fault types are below.


This is literally the smell of damp cardboard and indicates that the wine has some level of cork taint, known in the wine trade as trichloroanisole (most commonly referred to as TCA). This only happens of course with wines that have been traditionally enclosed with a cork.

Vinegar/sherry like aromas

If a wine smells of vinegar, or is Sherry-like (when it’s not a Sherry), this is a sign of an oxidised wine.


If a wine appears mouldy or earthy in character, this may be a sign of unhygienic winemaking equipment (a fault rarely found these days).


Sulphur is regularly used by winemakers (amongst other things it is an antioxidant and an antiseptic). Wines that have a sulphur related fault may, in extreme cases, show a rotten egg aroma.

Other faults

You may come across one or two other terms wine buffs use when talking about faults, such as phenolic aromas. These tend to be more contentious in the wine world as some people believe certain types of phenolic aroma (such as brettanomyces) are a Good Thing.

And then taste…or do you?

By now your eyes and nose will have done the majority of the work for you. There is little more that your taste buds can or perhaps will want to do. So what happens now?

When you feel like kicking up a fuss

In a restaurant

Tell the waiter/manager you think the wine is faulty. At this stage, the truth of the matter is that different restaurants have different approaches. Some will replace your wine without question, some will do a straightforward refund, and some will move you away from your original choice. Some, post tasting, may disagree with you (it does happen). Don’t let any of this put you off – if you are not happy, say so.

From a merchant

If you have a vacuvin (a device that literally sucks the air out of an opened bottle of wine), use this immediately. With very few exceptions wine that is left in contact with air for 2/3 days will deteriorate in quality, and merchants may be a bit tricky about taking back an expensive bottle that’s been opened a week ago, and is now oxidised (as they can’t taste it to corroborate your thoughts).

Bearing this in mind, it’s important to get the offending bottle back to the merchant promptly. Make sure you’ve got the receipt and be clear with the merchant on when you opened the bottle and how you opened it. As an example, some people decant mature red wine, and then pour the wine back into the bottle using a funnel in a process known as double decanting.

Again, different merchants have different policies for such returns, but if you follow our guidelines above, you should be in good shape.