The Different Faults Found in Wine
What are the most common wine faults?
The five common wine faults are cork taint, reduction, oxidation, heat damage, and volatile acidity (VA). Each produces distinctive aromas or flavours, from wet cardboard and rotten eggs to bruised apples and vinegar. Knowing these faults helps wine drinkers identify when a bottle isn't showing as it should.
After a long day, there’s nothing better than finally opening that bottle of wine you’ve been looking forward to.
So when the wine smells strange, tastes flat, or just doesn’t seem right, it can be a little heartbreaking.
The good news? Not every unusual aroma means a wine is faulty. Wine is full of complex aromas, and personal perception varies considerably. But there are several recognised wine faults that every wine drinker should know.
The most familiar is probably cork taint, but reduction, oxidation, heat damage and volatile acidity can also affect a wine.
Let's break them down.
1. Cork Taint: The Wet Cardboard Smell
If your wine smells like wet cardboard, damp newspaper, a musty cellar, or a wet dog, you may be dealing with cork taint.
The main culprit is 2,4,6-trichloroanisole, better known as TCA. It can develop when certain naturally occurring compounds interact with chlorine and mould. While natural cork is commonly associated with cork taint, TCA can also originate from contaminated winery environments, including wood and other materials.
The frustrating part? You can't spot TCA simply by looking at the cork.
TCA isn't considered a health risk at the levels associated with cork taint, but it can seriously suppress the wine's fruit and aroma, making the bottle unpleasant to drink.
And perception differs from person to person. Some people are much more sensitive to TCA than others.
The takeaway: If a wine smells musty, muted, or distinctly like wet cardboard, don't immediately assume that's how the wine was supposed to taste.
2. Reduction: When Wine Smells Like Rotten Eggs
Reduction is essentially the opposite side of the oxygen equation from oxidation.
Reductive winemaking limits a wine's exposure to oxygen, often using stainless-steel vessels and controlled winemaking techniques. This can help preserve freshness and fruit character.
The problem comes when reduction becomes excessive.
Too little oxygen can contribute to the formation of unpleasant sulfur compounds, producing aromas reminiscent of:
- Rotten eggs
- Boiled cabbage
- Garlic
- Rubber
- Struck matches
- Sewage or skunk
The good news is that some reductive aromas can sometimes dissipate when the wine is exposed to air.
The takeaway: Reduction isn't automatically a fault. Controlled reduction can be part of winemaking; excessive reduction can make a wine smell seriously funky.
3. Oxidation: When Wine Gets Too Much Oxygen
If reduction is associated with too little oxygen, oxidation happens when wine is exposed to too much oxygen.
Think about a freshly cut apple. Leave it exposed to air, and it gradually turns brown. Wine can undergo a similar transformation.
An oxidised wine may show:
- Duller or browner colour
- Faded fruit aromas
- Nutty or bruised-apple characters
- Cider-like flavours
- Sherry-like notes
Oxidation can happen at different stages, including during winemaking, after opening a bottle, or as an old wine reaches the end of its life.
It's worth remembering that some wines are deliberately made in an oxidative style. The key question is whether the character is intentional and appropriate for the wine.
The takeaway: Oxygen isn't automatically the enemy. It's about how much exposure the wine receives and whether that exposure is controlled.
4. Heat Damage: When Wine Gets Cooked
Wine doesn't enjoy being baked in the heat.
Heat damage, sometimes referred to as heat-affected or cooked wine, can occur when wine is exposed to excessive temperatures for an extended period.
The results can include:
- Flat or dull fruit
- Premature ageing
- Cooked or stewed flavours
- Browning or colour changes
- Increased risk of oxidation
Temperature fluctuations can be particularly problematic for bottles sealed with natural cork. Expansion and contraction can compromise the seal and increase the wine's exposure to oxygen.
This is why consistent storage conditions matter.
For long-term storage, a properly controlled wine environment is ideal. If you don't have a wine fridge, keep bottles somewhere cool, dark, and away from direct sunlight and large temperature swings.
The takeaway: Don't leave your best bottles sitting somewhere hot. Wine likes stability.
5. Volatile Acidity: When Wine Smells Like Vinegar
Volatile acidity (VA) refers to volatile acids present in wine, particularly acetic acid and compounds such as ethyl acetate.
The easiest way to recognise excessive VA?
Think vinegar or nail polish remover.
VA can become more of an issue when wine is exposed to oxygen or when microbial activity isn't adequately controlled. It can arise at different points in winemaking and ageing, including fermentation, barrel ageing, and prolonged oxygen exposure.
Good winery hygiene, temperature management, appropriate sulfur dioxide management, and oxygen control all play important roles in reducing the risk.
The takeaway: A little volatile acidity can occur naturally in wine, but excessive vinegar-like or solvent-like aromas can indicate a fault.
Quick Guide: Can You Spot These Wine Faults?
| Wine Fault | What You May Smell/Taste | Common Cause |
|---|---|---|
| Cork Taint (TCA) | Wet cardboard, musty cellar, damp dog | TCA contamination |
| Reduction | Rotten eggs, rubber, struck matches | Excessive lack of oxygen |
| Oxidation | Bruised apple, nuts, cider, Sherry | Excessive oxygen exposure |
| Heat Damage | Flat, cooked, stewed flavours | Excessive heat or temperature swings |
| Volatile Acidity | Vinegar, nail polish remover | Acetic acid/ethyl acetate and microbial activity |
Does a Faulty Wine Mean It's Unsafe?
Not necessarily. Many common wine faults are primarily quality and sensory issues rather than indications that the wine is dangerous to drink.
However, if a bottle seems genuinely spoiled or otherwise questionable, it's better not to drink it.
And remember: unusual doesn't always mean faulty.
Some wines are intentionally funky, oxidative, reductive, or highly aromatic. Wine styles can be surprising, especially with natural and minimal-intervention wines.
The real skill is learning to distinguish intentional character from a defect.
How to Tell If Your Wine Is Faulty
When something seems off, don't panic. Try this simple approach:
1. Smell it first.
Does it smell like wet cardboard, rotten eggs, vinegar or cooked fruit?
2. Taste it.
Does the palate confirm what your nose is telling you?
3. Give it some air.
Some reductive aromas can change or disappear with aeration.
4. Consider the wine's style.
Is the unusual character intentional?
5. Trust your senses — but question them.
Our ability to detect wine faults varies considerably, so don't be afraid to ask another experienced taster for a second opinion.
Final Pour
Learning about wine faults isn't about becoming the person who declares “CORKED!” after one sniff.
It's about becoming a more confident wine drinker.
Once you know what TCA, reduction, oxidation, heat damage, and volatile acidity smell and taste like, you'll have a much better reference point when something doesn't seem quite right.
And perhaps most importantly, you'll learn that wine isn't always about identifying what's wrong — it's about understanding why a wine tastes the way it does.
So next time a bottle smells a little suspicious, pause before pouring it down the sink. Give it a proper sniff, taste it, think about what you're experiencing — and trust your palate.
FAQs
What are the five common wine faults?
The five common wine faults are cork taint, reduction, oxidation, heat damage and volatile acidity. Each produces recognisable sensory characteristics that can affect the wine's aroma, flavour and overall balance.
How can you tell if wine is corked?
Corked wine often smells like wet cardboard, damp newspaper, a musty cellar or wet dog. The fruit aromas may also seem muted or suppressed. The main compound responsible is TCA.
Is corked wine safe to drink?
Cork taint is primarily a quality issue rather than a health concern. However, it can make the wine unpleasant to drink, so a heavily corked bottle is generally considered defective.
What does reduction smell like in wine?
Excessive reduction can produce rotten egg, garlic, rubber, boiled cabbage, struck-match or sewage-like aromas due to sulfur compounds.
What does oxidised wine taste like?
Oxidised wine may taste flat, tired or nutty, with flavours and aromas reminiscent of bruised apple, cider or Sherry. Some wines, however, are intentionally made with oxidative characteristics.
Can heat ruin wine?
Yes. Prolonged exposure to excessive heat can cause wine to lose freshness and develop flat, cooked or stewed characteristics. Temperature fluctuations can also increase the risk of oxidation, particularly in cork-sealed bottles.
What does volatile acidity smell like?
Excessive volatile acidity is commonly associated with vinegar-like aromas from acetic acid and nail-polish-remover or solvent-like aromas associated with ethyl acetate.
Is every unusual wine aroma a fault?
No. Some aromas that seem unusual can be intentional characteristics of a wine's grape variety, winemaking technique, age, or style. The key is determining whether the character is appropriate for that particular wine.