How to identify wine faults


Most of us think we know when our wine is faulty. But it's not always easy to pinpoint exactly why this might be. We name the top five things to look for if you think your wine is faulty

Wine faults are, sadly, all too common. A recent study by Wine Spectator revealed 7% of all bottled wines are faulty in some way. Fortunately, most wine merchants will replace your bottle if you think it is off.

Sometimes, however, the tell-tale signs of cork taint or wine faults can be hard to pinpoint and arguably are the intended characteristics of the wine. For this reason, we have isolated five common wine faults and the best ways to detect them. It should be noted that faults in small quantities are passable and can actually add character and enjoyment to a wine. However, if you are getting any of the pungent characteristics listed below, then we strongly recommend you replace the offending bottle.

Fault one: cork taint (trichloroanisole)

Contrary to popular belief, “corked wine” does not mean there are pieces of crumbled cork in the bottle. Cork taint or corked wine is the presence of a chemical containment called 2,4,6-Trichloroanisole (TCA) in your wine. Usually, this comes from the natural cork in the bottle; however, TCA can also be present in oak barrels or bottling lines. In this case, the entire batch of wine is ruined instead of just one bottle. For the record, TCA isn’t harmful, it just ruins your wine.

How to spot cork taint:

There is an unmistakable smell of mouldy basement, wet newspaper or musty cardboard. Fruit aromas and flavours will have dulled and there will generally be an overall loss of vibrancy in the wine.

Fault two: oxidation

Oxidised wine means the juice is spoiled from too much exposure to oxygen. If you open a bottle and leave it on your countertop for a week, it becomes oxidised – forever changing the flavour profile from fresh and vibrant to bitter and flat. Sometimes this happens before you have opened your wine due to a break in the closure or from being poorly sealed at the winery.

It should be noted that some wines are deliberately oxidative as the style the winemaker is trying to achieve, i.e. Sherry and Vin Jaune.

How to spot oxidisation in wine:

The major indicator for oxidised wine is the colour. Whites turn amber or even brown and reds start to turn brown or brick-coloured. Aromas in whites start to resemble Sherry or apple cider and reds take on a caramelised quality. Both whites and reds lose their fruit character and become more bitter.

Fault three: reduction

This is the opposite of oxidisation. Reduction occurs when the wine hasn't received enough exposure to oxygen during its production. Winemakers are well aware of the adverse effects of too much oxygen in their wines and can potentially counter this with reverse winemaking techniques. If taken to the extreme, reduction occurs.

How to spot reduction in wines:

Extremely reduced wines smell like sulphur, so if you notice a smell of rotten eggs and burnt rubber, your wine is likely reductive.

If your wine is reductive, it can be improved or even fixed by decanting or aerating the wine and/or putting copper into it (use a clean penny).

Fault four: high doses of volatile acidity

Volatile acidity (VA) occurs naturally in wine and in small doses it can actually add character. Some winemakers even use it deliberately to add complexity to the flavour profile. In high doses, VA will make your wine taste like vinegar or stomach acid. The cause of this is generally from bacteria in the wine that creates acetic acid (the same substance that gives vinegar its aroma and flavour) and its by-product ethyl acetate (which smells like nail polish remover).

How to spot high doses of volatile acidity in wines:

You will detect a violent smell of acetone, nail polish remover and/or vinegar. The wine will likely taste sharp and like vinegar as well.

Fault five: re-fermentation

This refers to fizzy red or white wine that isn't supposed to be frizzante. This occurs when residual sugar connects with any yeast after being bottled. This is most common when sweet wines have been bottled in unsterile conditions, allowing the presence of micro-organisms.

How to spot re-fermentation in wine:

This one is easy – your still wine is fizzy and has tiny bubbles. Do make sure you are certain the bubbles are not supposed to be there – some still wines like Vinho Verde are meant to be fizzy.

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