A bottle can look perfectly sound, carry a smart label and come from a producer you trust, yet still disappoint the moment it is opened. Learning how to identify wine faults helps you separate a genuinely flawed wine from one that is simply unfamiliar, youthful or not to your taste. It is a useful skill at a restaurant, at a dinner party and when opening something special at home.
The key is not to hunt for faults in every glass. Wine is naturally varied, and some of its most interesting aromas can be a little wild at first. Instead, look for smells or flavours that feel out of place, overpower everything else or make the wine seem lifeless and unpleasant.
What counts as a wine fault?
A wine fault is a problem caused by microbiology, oxygen, heat, a faulty closure or poor handling somewhere between winery and glass. It affects the wine’s intended character, often making it smell dull, stale, sour, mouldy or oddly artificial.
That is different from a wine style you do not enjoy. A pale, delicate Pinot Noir is not faulty because you wanted a fuller red. A bone-dry Muscadet is not flawed because it tastes sharp after a richer Chardonnay. Equally, a wine can be technically sound but too old, too young or simply poorly matched to the food.
Context matters. Many natural, low-intervention or traditionally made wines have savoury, hazy or yeasty notes that are intentional and enjoyable. The question is whether the wine feels balanced and alive, rather than whether it conforms to a single idea of what wine should smell like.
How to identify wine faults using your senses
You do not need a chemistry set or a sommelier’s vocabulary. Start by pouring a small measure, looking at it, smelling it before swirling, then tasting it. If something seems wrong, give the glass a gentle swirl and smell again. Some initially awkward aromas fade after a few minutes of air; true faults rarely improve much.
Start with the appearance
Colour can offer clues, although it cannot prove a fault on its own. A young white wine that is unusually deep gold or brown may have been oxidised. A red that has lost its brightness and looks brick-brown around the rim may be tired, particularly if it is much younger than expected.
Cloudiness is not automatically a problem. Unfiltered wines can be hazy, and harmless sediment is common in mature reds, vintage Port and some bottle-conditioned wines. Tiny crystals in the bottom of a white wine are tartrates, sometimes called wine diamonds. They are completely harmless and often a sign the wine has had minimal processing.
Be more cautious if a still wine is unexpectedly fizzy, especially if it also tastes yeasty, sour or stale. It may be undergoing an unwanted secondary fermentation in bottle. A little spritz can be deliberate in some fresh, youthful wines, so use the label, style and your senses together.
Trust your nose first
Most faults announce themselves on the nose. Cork taint is the one many drinkers know, though it is often misunderstood. A corked wine does not necessarily smell like cork. It is more likely to smell of damp cardboard, a musty cellar, mouldy newspaper or a wet dog. Fruit aromas become muted, and the palate feels stripped of life.
Cork taint is caused by a compound called TCA and can occur with natural cork, although it is far less common than it once was. It is not a criticism of the producer, merchant or person who opened the bottle. It is simply an unfortunate bottle fault.
Oxidation smells different. Think bruised apple, sherry-like nuttiness, stale cider or a wine that has been left open too long. In wines deliberately made in an oxidative style, such as some Sherries and Vin Jaune, those notes are the point. In a crisp Sauvignon Blanc or a young aromatic white, they are usually a warning sign.
A smell of struck matches, flint or gunpowder can cause confusion. In moderation, these reductive notes are part of the appeal of certain Chardonnays and other wines. If the aroma is more like rotten eggs, blocked drains, burnt rubber or overcooked cabbage, it has probably gone too far. Sometimes a few minutes in the glass helps. If it persists and masks the fruit, the bottle is unlikely to be showing well.
Then taste for balance and freshness
A faulty wine often confirms itself on the palate. Corked wine tastes dull and hollow. Oxidised wine can feel flat, browning and short. A wine affected by excessive volatile acidity may smell and taste sharply of vinegar, nail varnish remover or glue. Very small amounts can add lift and complexity, especially in certain traditional styles, but obvious solvent-like character is unpleasant.
Brettanomyces, usually shortened to Brett, is another divisive one. At low levels it can give a savoury, leathery or spicy edge to some reds. At higher levels it smells distinctly of sticking plasters, horse stable or medicinal cloves, and can bury the fruit. Whether you find a little Brett charming or distracting is partly personal taste. When it dominates, it is generally regarded as a fault.
Heat damage is often easier to recognise after tasting than smelling. A wine that has been badly stored or transported in hot conditions may taste stewed, jammy and oddly cooked, with little freshness and an alcoholic burn. In severe cases, the cork may push upwards or seepage may appear around the capsule. Do not confuse this with a naturally ripe, warm-climate red, which may be generous but should still feel composed.
Fault, flaw or just a bottle you do not like?
This distinction gives people confidence to speak honestly about wine without dismissing styles too quickly. If a wine tastes intensely tannic, highly acidic, smoky, floral or earthy, it may be doing exactly what it was made to do. Try asking whether the sensation is clean and balanced, even if it is not your favourite.
Serving temperature can also make a sound wine seem faulty. Whites served too cold lose aroma and can taste hard. Full-bodied reds served too warm become heavy and alcoholic. A white wine with a slightly muted nose may simply need ten minutes out of the fridge; a red that seems boozy can benefit from a short chill.
Food changes the picture as well. A dry, mineral white can seem severe on its own and brilliant with oysters, goat’s cheese or salty crisps. A young Barolo may feel stern before supper but make sense beside rich, slow-cooked food. Before declaring a fault, give the wine a little time and consider what it is being asked to do.
What to do when you think a bottle is faulty
If you are at home, keep the bottle, closure and remaining wine. Make a note of what you noticed and when you opened it. A specialist merchant will usually want to assess a suspected fault, and a short description such as damp cardboard, vinegar or cooked fruit is more useful than simply saying you did not like it.
At a restaurant, it is entirely reasonable to mention a suspected fault politely. You are not being difficult by saying that the wine smells corked or oxidised. The person serving you will normally check it and replace it if they agree. There is no need to finish a faulty glass to prove the point.
One useful habit is to revisit the glass after ten or fifteen minutes. Some wines open beautifully, while a fault becomes clearer as the fruit fails to emerge. If you are unsure, compare notes with someone else at the table. Fresh eyes and noses are remarkably helpful.
Wine is allowed to be surprising. The pleasure lies partly in recognising when a strange note is a producer’s signature, when it needs a little air, and when the bottle has genuinely missed the mark. Bring a suspect bottle into Givino and ask us about it - a good conversation is often the quickest route to enjoying the next glass more.
