What Are the Most Common Wine Faults?

Jun 1, 2025by David Bachus

Short answer: The most common wine faults are cork taint, oxidation, heat damage, and reduction. These flaws can affect aroma, flavor, and drinkability - and even expensive wines aren’t immune.

Here’s how to spot them, what causes them, and whether the wine is still safe to drink.

1. Cork Taint (a.k.a. “Corked” Wine)

What it smells like:
Wet cardboard, moldy basement, soggy newspaper

What causes it:
Cork taint comes from a compound called TCA (2,4,6-trichloroanisole) - often transferred to wine from a natural cork that was infected.

How it affects the wine:
It dulls the fruit, mutes aromas, and makes the wine flat and lifeless. Some bottles are mildly affected; others are undrinkable.

Can you fix it?
No. Once corked, always corked.

2. Oxidation

What it smells like:
Sherry, bruised apple, stale nuts

What causes it:
Too much oxygen exposure - either during winemaking, faulty corks, or long storage after opening.

How it affects the wine:
The wine loses its freshness, color fades (whites turn amber; reds go brick-orange), and flavors feel tired.

Can you drink it?
It won’t make you sick, but the wine may taste past its prime.

3. Heat Damage ("Cooked" Wine)

What it smells/tastes like:
Stewed fruit, prunes, flat or jammy flavors

What causes it:
Exposure to high temperatures during shipping or storage (often over 75°F / 24°C).

How it affects the wine:
The wine becomes flabby and disjointed. You might notice a pushed-out cork or leaking capsule - both signs that heat compromised the seal and allowed oxygen in.

Can you drink it?
Yes, but expect dulled complexity and premature aging.

4. Reduction

What it smells like:
Burnt rubber, rotten eggs, struck match, garlic

What causes it:
Too little oxygen during winemaking or bottling — the opposite of oxidation.

How it affects the wine:
Reductive aromas can mask fruit and complexity. Some blow off with swirling or decanting, others stay put.

Can you fix it?
Sometimes airing the wine helps. If not, it’s a fault.

5. Brettanomyces (a.k.a. “Brett”)

What it smells like:
Barnyard, leather, sweaty saddle, Band-Aids

What causes it:
A wild yeast (Brettanomyces) that sneaks into the cellar during winemaking or aging.

How it affects the wine:
In small amounts, some consider it charming or “Old World.” In excess, it overwhelms the fruit and becomes a flaw.

Can you drink it?
Yes - it’s subjective. Some love a little Brett; others can’t stand it.

6. Volatile Acidity (VA)

What it smells like:
Nail polish remover, vinegar

What causes it:
Acetic acid or ethyl acetate buildup, often from poor hygiene during winemaking or uncontrolled fermentation.

How it affects the wine:
VA gives wine a sharp, sour bite and unpleasant chemical aromas.

Can you drink it?
Low levels are tolerable in some styles (e.g., natural wines), but high VA usually signals spoilage.

Bottom Line: How Do You Know If a Wine Is Faulty?

If your wine smells “off,” tastes flat, or lacks fruit and balance, it could be flawed.
Common signs include:

  • A musty or moldy nose

  • Leaking or pushed-out cork

  • Brownish or dull color

  • Burnt rubber or chemical notes

Not all wine flaws are dangerous, but they can make even a great bottle a disappointment.
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