Wine ยท Faults
Common wine faults and how to spot them
Knowing faults helps you serve with confidence and answer exam questions on what went wrong.
A fault is a flaw in a wine, not simply a style you dislike. Tell the difference by smell first.
The main faults
- Cork taint (TCA): smells of damp cardboard or a wet basement and mutes the fruit. It comes from a chemical compound in the cork and can affect any cork-sealed bottle.
- Oxidation: too much oxygen makes wine smell of bruised apple, nuts or stewed fruit, and colour darkens. Some styles, such as Oloroso Sherry, are made on purpose to be oxidative; in a fresh white it is a fault.
- Reduction: too little oxygen during winemaking can cause smells of struck match, rubber or boiled egg. It often blows off with air.
- Volatile acidity: a vinegar or nail-polish note from acetic acid.
- Brettanomyces: a spoilage yeast that gives barnyard, sweaty saddle or medicinal notes. A little may be tolerated by some tasters; a lot is a fault.
- Heat damage: cooked, jammy aromas, sometimes with a pushed-up cork or leakage after storage in a hot place.
- Light strike: wines in clear bottles exposed to light can develop cabbage or wet-wool notes.
- Refermentation: unexpected fizz in a still wine means yeast restarted in the bottle.
Not faults
- Tartrate crystals: harmless sediment sometimes found in white wine bottles.
- Natural sediment in older red wines.
- A style you do not like: high tannin or high acidity is not a fault.
What to do in service
If a guest believes a wine is faulty, do not argue. Smell it yourself, offer a replacement where policy allows and note it for the supplier. Venue policy decides the details.
Note: this is a general study guide written in our own words, not WSET's syllabus. For what is examined, always check WSET's published specification and your course provider.
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