Learn
When something is wrong with a bottle
What a faulty wine smells like, and what is actually harmless.
The short answer
Most bottles are fine. The two faults worth recognising are cork taint, which smells of damp cardboard and mutes the fruit, and oxidation, which makes a wine taste flat and stale. Neither will do you any harm.
Overview
Most of what worries people is fine. Crystals in the bottom are harmless. Sediment in an old red is normal. Cloudiness is often deliberate.
The fault worth learning is cork taint. A corked wine smells of wet cardboard, damp basement or musty newspaper, and the fruit seems stripped out. It affects a small percentage of cork-sealed bottles and is not your fault.
Other signs of a problem: vinegar or nail-polish smells, browning colour in a young wine, or a cork pushed proud of the bottle.
Rotten-egg smells are worth decanting vigorously first — reduction often disperses with air, and then the wine is fine.
No wine fault will make you ill. They are unpleasant, not dangerous.
If a bottle is faulty, return it. Retailers and restaurants expect this and it is a normal part of the trade.
Where you can see it
- Corked
- Damp cardboard, wet newspaper, or simply a wine that seems to have lost its smell. Bits of cork floating in the glass are unrelated and harmless.
- Not a fault
- Crystals at the bottom of a white, or sediment in an old red. Both are normal and neither affects flavour.
What people get wrong
2 widely repeated claims this page corrects.
Not true
“The wine is corked — look, there is cork floating in it.”
Cork fragments are an opening accident and are harmless. "Corked" means contaminated by TCA, which smells of damp cardboard and wet dog, and it can happen with no visible cork at all.
Depends
“If it smells nutty and oxidised, the wine is broken.”
Accidental oxidation is a fault. Deliberate oxidative ageing is a category of great wine — Oloroso, Madeira, Vin Jaune, Tawny Port — and the same aromas mean opposite things in the two cases.
Go shallower or deeper
The beginner page and the chemistry page are both correct, and neither substitutes for the other.
Go deeper
Reduction: sulfur compounds and struck-match aromas
Low-oxygen conditions can leave volatile sulfur compounds in a wine — some transient and prized, some genuinely faulty.
Go deeper
Oxidation: the chemistry, the fault and the style
The same reactions that ruin a forgotten bottle also produce Oloroso, Madeira and Vin Jaune. Intent is what separates them.
Go deeper
Volatile phenols: smoke, spice and sticking plaster
One compound family behind three very different things — oak toast character, Brettanomyces spoilage, and smoke taint.
Sources
Sources consulted