A practical, confidence-boosting guide to common wine faults and how to spot them
If a wine smells like wet cardboard, a petting zoo, or yesterday’s salad dressing, you’re not “being difficult”—you might be right. Faults happen from the cellar to the supply chain, and learning to recognize them helps you send a bottle back (politely), troubleshoot storage, and trust your palate.
Below you’ll find the most common faults, what causes them, how they show up in the glass, quick checks to confirm, and what to do next—grounded in respected wine-education sources.
1) Cork taint (corked / TCA)
What it is: Contamination—usually from a natural cork—by 2,4,6-trichloroanisole (TCA), which mutes fruit and adds musty aromas.
How it smells/tastes: Wet newspaper, damp basement, moldy cardboard; the wine feels dull and lifeless.
Quick checks: If you suspect TCA, ask for a fresh bottle; comparing side-by-side is the fastest confirmation. Remember: cork bits in the glass ≠ “corked.”
What to do: Return or exchange it. It’s not harmful, just unpleasant.
2) Brettanomyces (Brett)
What it is: A spoilage yeast that can contribute earthy, animal, and medicinal notes; low levels are stylistically tolerated by some producers, but higher levels overwhelm fruit.
How it smells/tastes: Barnyard, horse blanket/sweaty saddle, Band-Aid/medicinal, clove/spice; often a metallic, hard finish.
Quick checks: Aeration won’t “fix” Brett; if the profile dominates and fruit is suppressed, treat it as a fault rather than “savory complexity.”
What to do: If you dislike it (or it masks varietal character), send it back. Preference varies, but intensity matters.
3) Light damage (lightstrike / sometimes called light shock)
What it is: UV/blue light reacts with riboflavin and amino acids, forming pungent sulfur compounds that clobber fruit—especially in delicate whites and sparkling wines, and in clear/green glass.
How it smells/tastes: Damp cardboard, overcooked cabbage, wet wool; fruit tastes faded or stale.
Quick checks: Was the bottle stored in bright retail windows or sunlit shelves? Champagne and Pinot Grigio in clear glass are common victims.
What to do: There’s no fix—swap the bottle and store replacements away from light.
4) Temperature mismanagement (heat damage & big temperature swings)
What it is: Prolonged heat (e.g., hot car, sunny window, warm warehouse) “cooks” wine; heat expansion can push the cork, breaking the seal and accelerating oxidation. Wide swings are also harmful.
How it smells/tastes: Jammy, baked, caramelized apple/nutty notes; dulled fruit; sometimes seepage under capsule or a popped cork.
Quick checks: Look for leakage, sticky capsules, unusually low fill, or a cork raised above the lip.
What to do: Return it; at home, aim for a constant storage temperature of 55°F in darkness.
5) Dry, cracked corks → premature oxygenation
What it is: Low humidity or long upright storage dries natural corks; they shrink, letting oxygen in and aging the wine too fast.
How it shows up: Oxidized aromas (bruised apple/nutty notes), faded fruit, advanced color; cork may crumble on opening.
Prevention: Store bottles on their sides and maintain approximately 50–80% humidity for long-term cellaring.
6) Past-its-best (over-mature / over-aged)
What it is: Wine aged beyond its optimal window loses freshness, definition, and structure—even if perfectly stored.
How it smells/tastes: Faded color, dull fruit, drying tannins, tired palate; can overlap with oxidation.
What to do: Not a “fault” from mishandling so much as time; open younger bottles or choose producers/vintages meant for aging.
7) Volatile acidity (VA)
What it is: Elevated acetic acid/ethyl acetate from certain yeasts/bacteria during fermentation or poor hygiene; tiny amounts can add lift, but excess smells/tastes like vinegar/nail-polish remover.
How it smells/tastes: Balsamic/vinegar edge; prickly, solvent-like top note (ethyl acetate).
Quick checks: If a brief swirl intensifies a salad-dressing vibe and fruit disappears, VA is likely high.
8) Reduction (sulfur-driven stink from too little oxygen exposure)
What it is: In low-oxygen conditions, volatile sulfur compounds (VSCs) such as hydrogen sulfide and mercaptans form; a little “struck match” can be intentional, but overt reduction is a fault.
How it smells/tastes: Rotten egg, blocked drain, burnt rubber, skunky/cabbage; fruit feels trapped underneath.
Quick checks: Give a vigorous swirl or short decant—light sulfury notes can blow off; if it persists as H₂S/mercaptans, it won’t disappear in the glass.
What to do: If aeration doesn’t help, return it.
*Some wines are intentionally made in a reductive wine style, and it is not a fault. Many Burgundian white wines are vinified with a very protective winemaking process. These wines may have an aroma of struck matches without being over-reductive.
Bonus: How to build your “faults” muscle (and stay objective)
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Use a method. Pros work through sight–nose–palate systematically; a consistent grid helps you separate “style” from “spoilage.”
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Control the variables. Taste in neutral stems, at proper temperature, and away from strong smells; compare a second bottle when in doubt.
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Know what’s not a fault. Tartrate “wine diamonds,” sediment, or intentional slight spritz in some styles aren’t faults.
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Store smart. Cool (≈55°F), dark, still, and sideways for cork-closed bottles; maintain moderate humidity to protect corks.
A quick decision tree
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Something smells off.
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Musty/cardboard? → Likely TCA → ask for a replacement.
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Barnyard/Band-Aid? → Brett → acceptable to some at very low levels; replace if it dominates.
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Vinegar/nail polish? → High VA → replace.
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Rotten egg/skunky? → Reduction → swirl/decant; if it persists, replace.
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Cabbage/wet wool with faded fruit (esp. whites/sparkling)? → Lightstrike → replace.
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Bottle looks suspicious.
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Cork pushed up, seepage, very low fill? → Heat damage/oxidation → replace.
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Crumbly dry corks and tired flavors? → Premature oxidation from cork desiccation → fix storage going forward.
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Still unsure?
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Ask for a second bottle/glass—it’s a standard hospitality practice, and your palate deserves a fair shot.
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Bottom line: trust yourself
Many faults are unmistakable once you know the signs, and sensitivity varies—so if it smells wrong to you, you’re not imagining it. With a simple, systematic approach (and better storage habits), you’ll separate personal taste from true faults with confidence. It may not just be you!