Faults
What is wrong with my wine?
21 things that can be wrong with a bottle — and several that look wrong but are not. Most people arriving here are worried about something harmless.
Faulty wine is unpleasant, not dangerous. Alcohol and acidity make wine a hostile environment for anything that would make you ill. You may have wasted an evening; you have not poisoned yourself.
4 of the things listed here are not faults at all. Crystals in the bottom of the glass, sediment in an older red, a cork that crumbled — all fine, all common, and all responsible for a great deal of unnecessary worry.
Work it out from what you noticed
Tool
Fault troubleshooter
Tick what you can smell, taste or see and get a ranked diagnosis, with an honest statement of how confident it is and what would tell the close calls apart.
Genuine faults
Something has gone wrong. The wine is spoiled, though not unsafe.
Cork taint (TCA)
The classic "corked" wine: musty, damp-cardboard aromas that strip a wine of its fruit. Harmless to drink, but the bottle is spoiled.
Heat damage
Wine cooked in transit or storage — stewed, flat fruit, often with a pushed-up cork or seepage as evidence.
Light strike
Damage from light exposure, producing cooked-cabbage and wet-wool aromas. Most common in clear bottles.
Unintended refermentation
A still wine that has started fermenting again in the bottle — fizzy when it should not be, and often cloudy with it.
Excessive sulfur dioxide
A sharp, catchy smell like a struck match or a just-lit firework, sometimes prickling the nose or throat.
Smoke taint
Ashtray and burnt aromas in wine from vineyards exposed to bushfire smoke — an increasingly significant problem.
Microbial spoilage in an opened or damaged bottle
Visible growth, a film on the surface or a putrid smell — the one group of conditions where the honest answer is to pour it away.
Mousiness
A distinctive stale-popcorn or mouse-cage aftertaste that appears only after swallowing — and which some people cannot detect at all.
Premature oxidation (premox)
White wines — famously white Burgundy — oxidising years earlier than they should. A real and only partly explained phenomenon.
Geranium taint
A distinct crushed-geranium-leaf smell caused by lactic acid bacteria acting on sorbic acid.
Ropiness
A rare bacterial spoilage giving wine an oily, viscous, slightly slimy texture.
Depends on the wine
A fault in one style and a deliberate feature in another. Oxidation is a flaw in young Sauvignon Blanc and the entire point of Oloroso sherry.
Oxidation
Wine that has had too much contact with air — browning in colour, with bruised-apple and nutty notes in place of fresh fruit.
Volatile acidity (VA)
Vinegar and nail-polish notes, produced by acetic acid bacteria. A small amount adds lift; too much is a clear fault.
Reduction
Rotten-egg, struck-match or drain-like aromas from a wine deprived of oxygen. Often blows off with air; sometimes it does not.
Haze and cloudiness
A wine that is not clear. Usually harmless — often deliberate — but occasionally a sign of microbial spoilage.
Genuinely argued about
Experienced tasters disagree about whether these are faults at all. WineHQ presents the disagreement rather than picking a side.
Brettanomyces (Brett)
A spoilage yeast producing barnyard, plaster and sticking-plaster aromas. Genuinely divisive: a fault to some, complexity to others.
Burnt rubber character
A burnt-rubber or acetone note historically associated with some South African wine, and much argued over.
Harmless — not faults at all
The things people most often mistake for spoilage. All of these are fine.
Tartrate crystals
Harmless clear or coloured crystals that look like glass or sugar. Not a fault, and often a sign of gentle winemaking.
Sediment
Dark deposit in aged red wine, made of tannin and colour compounds that have polymerised and dropped out. Entirely normal.
A crumbling or broken cork
A cork that breaks apart during opening. Annoying, and — despite the name — nothing to do with a wine being "corked".
Protein haze
A soft haze in white wine caused by unstable proteins, usually triggered by warmth.
Related
Tool
Storage conditions check
Several of these faults are storage problems rather than winery problems. This assesses where you keep your wine.
Winemaking
How wine is made
Most faults are a normal process that went further than intended. The process pages explain what was supposed to happen.
Glossary
Glossary
TCA, mercaptans, volatile acidity, tartrates — the words, defined.