6 of the most common wine faults (and how to pick them)

Have you ever tried a wine and thought it tasted beyond a little strange? Maybe it was a bit funky – but not in a good way. While it doesn’t happen very often, wine can have faults. These can be so subtle that most people won’t even realise, but other times, they can’t be missed. When a fault is that noticeable, a wine’s aromas and flavours will seem a little off, even if you can’t say why. But these obvious faults are the best ones to try because their tell-tale signs tend to stay with you, helping you to spot them in more subtle cases. 

While the less we know about wine faults, the more likely we are to enjoy every bottle we open, it would also mean not seeing wines at their best. And after producers spend a year in the vines on the one vintage, and even longer in the winery making and maturing their wines, they’d hate for us to try them when they’re not in peak condition. Some faults can show in just one bottle of an entire release – they often occur long after they’ve left the winery – so you might forever avoid a wine you thought you didn’t like when it could be right up your alley.

So, what are the most common types of wine faults? And how can you pick them? Below, we run through some of the key issues below, with a few pointers for sniffing them out.

Unless you’re drinking loads of Champagne, international wines and pinnacle Aussie releases, you don’t need to worry about cork taint thanks to the mass introduction of screwcaps in Australia. Various top local producers have since returned to cork after a sharp rise in its quality, but still, cork-sealed bottles remain at risk of being ‘corked’. 

Cork taint is when a wine has the chemical compound 2,4,6-trichloraanisole, AKA TCA, which is transferred from, and through, the cork. It introduces mould-like characters to a wine that are often likened to wet dog and damp cardboard. It’s musty, much like when you rediscover that load of wet washing in the machine a day or two later. If you see a wine pro sniffing the cork of a freshly opened bottle, they’re likely trying to avoid cork taint.

The signs of cork taint can be super subtle, but as you continue to pour out a bottle, they can become more pronounced. Cork taint will generally spoil a wine – and your enjoyment of it. 

Wine doesn’t love extreme temperatures, and excess heat is one of the quickest ways to ruin a bottle. This is particularly good to remember for any future cellar-door adventures – you’ll want to avoid stashing any just-bought bottles in a hot car (bring an esky or chiller bag so you can linger for that long lunch). 

Unsurprisingly, high temperatures will cook a wine, so when you open the bottle, it might have stewed-like aromas, taste jammy or sour, and, in some cases, look darker than it should. Heat damage often happens when wine is in transit, perhaps sitting in the sun on a dock or outside a warehouse for too long before moving on to its next destination. 

While heat damage generally occurs before you buy a wine, it’s something to consider when storing bottles at home – always use the coolest room in the house.

Brett has some distinctive trademark smells and flavours that range from dirty socks and Band-Aids to gas, barnyard and horsey characters. As gross as it all sounds, these traits can often go unnoticed in a wine. In fact, some producers still see a minimal presence of brett as a positive in their wine and they consciously work to incorporate it, although that’s not so much the case here in Australia these days. 

Brettanomyces is a type of naturally occurring wild yeast that can find its way into wine in various ways, often coming off a winery’s equipment or barrels, or even inside wine bottles. It most commonly affects red wines and tends to lessen a wine’s length – or how long its flavours linger after the mouthful is gone. Brett can dull a wine’s characters and it can also leave a metallic taste on the finish. 

In extreme cases, brett will ruin a wine as well as your threshold for it in the future – it has the kind of stink that your ‘palate memory’ doesn’t forget.

Volatile acidity, or VA, can sometimes be easier to spot in a wine than other faults because it will smell like vinegar or even nail polish remover. It comes from the compounds found in certain types of acid and, much like brett, some producers still see a touch of VA as a positive thing because in small doses, it can lift a wine. Too much, however, and you’re at the nail salon. 

The thing with VA is it can get more enhanced with time, so while you may not notice it on your first sip, as the wine warms in your glass, it can become much more obvious. One of the ways producers can combat VA is with the use of sulphur dioxide during the production process, and with more producers choosing not to add sulphur, or instead use it in very small quantities, it does still turn up. However, as mentioned, it’s not always considered a bad thing in mild cases. 

Oxidisation is what happens when a wine is exposed to air, which kicks off a chemical reaction that can turn down the volume of a wine’s colours and flavours. All those lovely bright, fresh characters can become muted and even show a little cider-like. It tends to be more common in white wines (the tannins in reds help to protect them, but not always), and extreme cases will have an overly developed colour. A white wine that should look clear and light, for example, can appear much more yellowed and even have brown tinges. 

Oxidisation can happen at various points in a wine’s life, but it’s often through older corks or poor seals – screwcaps are still susceptible – allowing too much air into a bottle over time. Oxidisation is also why you won’t love a glass of wine that’s been sitting out for a day or two.

Wines that have been damaged through exposure to UV light are also referred to as light-struck, and clear glass bottles are more vulnerable to it. This means it’s more common in whites and rosés – the types of wines typically found in clear bottles. It doesn’t take long for a bottle’s exposure to UV light to do its thing – it triggers a reaction within the wine that produces certain sulphur compounds that aren’t so enticing. Think gassy characters, like egg or cabbage. Ooft.

One of the fastest ways a wine will be damaged in this way is when it’s displayed in a window of a shop or a bar that’s exposed to sunlight – all those shiny bottles that catch your eye in a shopfront should be for display only. Harsh fluoro lighting can also do the same thing, so this is good to keep in mind when browsing in stores, too.