Wine faults: symptoms, causes and what to do

A faulty wine shows a persistent, recognisable quality failure, while a wine you simply do not like may be sound but unsuitable for your preferences. AWRI catalogues recognised wine faults and taints by their characteristic smells, allowing a taster to compare a specific observation with a published sensory reference. A general reaction that a wine is unpleasant is not enough by itself to establish a wine fault.

A sound wine may be firm, bitter, acidic, tannic, sweet, smoky, earthy or strongly oaked. Those characteristics can be unwelcome to an individual drinker without representing a quality failure. A sound wine may also seem muted, broad or awkward when its serving condition is unsuitable. VinSip's wine serving temperature guide explains how temperature changes the way aroma, alcohol, acidity and structure are perceived.

Begin with a clean glass and describe what the wine smells like before deciding whether the bottle is faulty. AWRI's recognised sensory categories provide the reference for descriptions such as damp cardboard for cork taint, bruised apple for oxidation, struck match or rotten egg for reduction, cooked fruit for heat-related deterioration and vinegar for volatile acidity. Descriptive language is more useful than a broad judgement because another person can smell the wine and check the same sign.

Fruit intensity also matters. AWRI's description of cork taint is relevant when a wine smells musty, but TCA can also suppress fruit and leave a wine unexpectedly empty or stale. A bottle therefore need not smell dramatically mouldy to justify closer assessment. The combination of muted fruit and a persistent damp or musty aroma is more informative than the condition or appearance of the closure.

Context should support the sensory diagnosis rather than replace it. A warm glass can exaggerate broad aromas, while a cold glass can conceal aroma and make a sound wine seem closed. Exposure to air can soften some reduction-related aromas, but air does not provide a general cure for every wine that smells unusual. VinSip's wine tasting guide provides a structured way to separate appearance, aroma, flavour, structure and overall judgement.

The table is a diagnostic aid rather than proof that every example of an unusual aroma is defective. AWRI's catalogue distinguishes recognised wine faults and taints from personal impressions, but a taster must still consider the intended style of the wine. Nutty or oxidative aromas may be deliberate in some styles, while smoky, earthy or savoury aromas may be normal expressions of production, grape variety or maturity.

A tasting record should separate observation from judgement. Write “damp cardboard” rather than “awful,” “bruised apple” rather than “old,” or “rotten egg” rather than “bad.” AWRI's sensory catalogue can then be used as the reference against which the observation is checked. This method also makes a complaint clearer because the restaurant or retailer can assess the same sensory sign.

Keep the remaining wine and bottle available if an assessment or return may be requested. A seller cannot examine wine that has been discarded, and the bottle may provide useful context through its closure, capsule, fill and signs of seepage. The sensory evidence should remain central, but preserving the bottle gives the restaurant or retailer a fair opportunity to confirm the concern.

A corked wine commonly smells of damp cardboard, musty paper, mouldy cloth, a wet cellar or a stale and muted version of its expected fruit. Cork taint is caused by 2,4,6-trichloroanisole, known as TCA, and AWRI includes cork taint in its catalogue of recognised wine faults and taints. The most useful evidence is the aroma in the glass rather than the appearance of the cork.

TCA can add a musty character and suppress fruit at the same time. AWRI's sensory reference therefore helps explain why a corked wine may seem strangely empty, dull or stripped of aroma without smelling strongly mouldy. A persistent combination of muted fruit and damp or musty character is more persuasive than a vague sense that the wine lacks excitement.

The phrase “corked wine” refers to cork taint, not every disappointing bottle opened with a natural cork. A crumbly, stained or wet cork does not by itself establish cork taint, while a clean-looking cork does not rule it out. The closure can provide context about the bottle, but the diagnosis depends on the wine's sensory character.

AWRI reports that some assessors detect TCA in wine below 1 nanogram per litre. AWRI also reports that sensory thresholds are generally lower in white wine, at around 3 to 7 nanograms per litre, than in red wine, at around 8 to 15 nanograms per litre. Differences in individual sensitivity and wine style can therefore lead careful tasters to disagree honestly about the same suspected bottle.

The reported thresholds are sensory thresholds rather than a guarantee that every assessor will respond identically. AWRI's figures indicate that TCA can be detected at extremely low concentrations and that the surrounding wine influences how readily the character is noticed. A delicate white wine may reveal a musty character differently from a fuller red wine, while a taster who is less sensitive may notice only that the fruit seems subdued.

Exposure to air does not remove TCA from cork-tainted wine. Swirling or decanting can make a sound wine more expressive, but a persistent musty character and suppressed fruit remain reasons to ask for assessment. Waiting may even make the contrast between the missing fruit and the unwanted aroma easier to recognise.

Cork taint should not be diagnosed from ordinary earthy, forest-floor or mature aromas alone. AWRI's catalogue is useful because the recognised sensory reference combines the musty character with a loss or suppression of expected fruit. A mature wine can show developed aromas while retaining coherence, balance and identifiable wine character; a cork-tainted wine often seems dulled and stripped.

At a restaurant, describe the smell and invite the server to assess the glass. “The wine smells of damp cardboard and the fruit seems muted” is more precise than saying that the bottle is bad. A restaurant can then compare the wine with another bottle or ask a knowledgeable staff member to check the same sensory signs.

For a retail purchase, keep the bottle, remaining wine, closure and proof of purchase where possible. Tell the retailer that the concern is cork taint caused by TCA and describe the damp, musty or fruit-suppressing character. The retailer then has a sensory description and physical bottle to examine rather than a report based only on preference.

The European Commission sets out the oenological practices and permitted substances that govern winemaking in the European Union in Commission Regulation (EU) 2019/934. That regulatory framework concerns permitted production practices and substances, while the consumer's practical recognition of cork taint remains sensory. AWRI's catalogue supplies the relevant smell-based reference for identifying the problem in a poured glass.

A sherry-like, bruised-apple, stale-nut or browned-fruit aroma often points to oxidation when that character is unwanted for the wine's intended style. AWRI catalogues oxidation among recognised wine faults and taints and provides sensory descriptions against which a taster can compare the bottle. The diagnosis should account for style because some wines are deliberately made with oxidative character.

An intentionally oxidative wine is not faulty merely because it smells nutty or sherry-like. The useful question is whether the character belongs to the expected style and remains balanced by freshness, structure and identifiable wine character. Oxidation becomes a practical fault diagnosis when an ordinarily fresh or fruit-led wine instead seems stale, browned, tired or depleted.

Exposure to air does not restore freshness that unwanted oxidation has already removed. Decanting may release aroma from a closed but sound wine, yet it cannot recreate fruit character lost through oxidation. A newly opened bottle that remains dominated by bruised apple, stale nuts or an inappropriate sherry-like aroma is therefore unlikely to recover through further waiting.

Serving temperature can briefly imitate some aspects of a tired wine. VinSip's wine serving temperature guide explains how excessive warmth can broaden aroma and emphasise alcohol, while excessive cold can mute fruit and aroma. Correcting the serving condition may improve a sound wine, but a persistent bruised-apple or stale-sherry character still supports an oxidation diagnosis.

Storage history supplies context for oxidation without replacing sensory evidence. VinSip's guide to how to store wine explains the value of stable, protected conditions, while VinSip's guide to how long wine lasts discusses the distinction between gradual development and deterioration after opening or storage. Aroma alone may not reveal the full history of a bottle, but a compromised closure, seepage or unsuitable storage can support the diagnosis.

Maturity is not automatically oxidation. A developed wine can show dried fruit, nuts, savoury aromas or diminished primary fruit while remaining balanced and appropriate for its style. AWRI's sensory categories are most useful when a taster identifies a dominant unwanted character rather than assuming that every mature aroma represents a fault.

Colour can provide supporting evidence, but colour should not be used alone. A wine may naturally deepen or change in appearance through grape variety, production method or maturation. The stronger practical case for oxidation combines an inappropriate browned or stale character with a loss of expected freshness and fruit.

Physical bottle signs can also support the assessment. A compromised seal, leakage or unexpectedly low fill may suggest that the wine has not remained properly protected, but those signs do not replace smelling and tasting the wine. The bottle's condition is contextual evidence, while the unwanted sensory character is the central evidence.

If a newly opened bottle appears oxidised, retain enough wine for the restaurant or retailer to assess. Describe the specific aroma, explain why it seems inconsistent with the expected style and avoid relying on broad words such as old or bad. A clear report of bruised apple, stale nuts or unwanted sherry-like character gives the seller a practical basis for checking the bottle.

Origin and production rules may help establish stylistic expectations. VinSip's guide to wine appellations explained describes how geographical origin and production rules can shape the type of wine a buyer reasonably expects. An appellation does not prove that an individual bottle is sound, but it can help determine whether oxidative character is intentional or inconsistent with the style.

A struck-match, flinty or smoky smell commonly points to reduction, while a rotten-egg, drain-like or strongly sulphurous smell may indicate a more severe expression of reduction. AWRI catalogues these sensory signs among recognised wine faults and taints. Some reduction-related aromas may lessen after the wine is exposed to air, so reassessment is useful before the bottle is rejected.

Start by swirling the wine in a clean glass and smelling it again after exposure to air. A mild struck-match character may fade enough for the underlying fruit to become clearer. A persistent rotten-egg or drain-like character is a stronger quality concern, particularly when the aroma continues to dominate the wine after aeration.

Pouring the wine into a larger vessel can provide more contact with air, but the purpose is assessment rather than a guaranteed cure. Reduction can behave differently from cork taint and oxidation because some reduction-related aromas are responsive to air. If the unwanted aroma remains dominant, continued waiting is not a reason to accept a bottle that fails to show its intended character.

A brief opening aroma should be distinguished from a settled diagnosis. Wine can release transient smells immediately after a bottle is opened, and those smells may change as the wine sits in the glass. AWRI's sensory framework is most useful when the taster identifies a recognisable aroma, exposes the wine to air and then checks whether that same aroma persists.

Reduction is not the same concept as sulphite labelling. The European Commission requires wine sold in the European Union to carry the statement “contains sulphites” above 10 mg per litre of total sulphur dioxide. That label communicates the presence of sulphites above the European Union labelling level; it does not state that a particular wine will smell of struck match, rotten egg or drains.

The European Commission sets European Union total sulphur dioxide limits at 150 mg per litre for dry red wine and 200 mg per litre for dry white and rosé, with higher limits for wines containing more residual sugar. Those regulatory limits do not diagnose the smell in an individual glass. AWRI's catalogue of recognised aromas, together with the wine's response to air, is the relevant sensory basis for identifying reduction.

The distinction matters because a consumer may see “contains sulphites” on a sound bottle and assume that the wording predicts an unpleasant sulphurous smell. European Commission labelling rules address total sulphur dioxide, while AWRI's fault references address sensory recognition. The label and the aroma therefore answer different questions.

Organic production does not by itself establish whether a wine will be reduced, oxidised, cork tainted or free from recognised wine faults. VinSip's guide to organic wine explains the production and labelling context, while AWRI's sensory catalogue remains the practical reference for the smell in the glass. Diagnosis should be based on the observed aroma and whether exposure to air changes it.

Smoky character also requires careful interpretation because smoke, flint and struck-match impressions may be used positively in descriptions of some wine styles. The relevant question is whether the character is integrated and appropriate or whether it dominates the wine and obscures fruit. An aroma does not become a fault merely because the descriptor sounds unusual.

If a sulphurous smell clears and the wine becomes expressive and balanced, the initial reduction may not justify a return. If rotten-egg, drain-like or similarly intrusive character persists and overwhelms the wine, ask the restaurant or retailer to assess the bottle. Explain that the wine was exposed to air and that the recognisable reduction-related aroma remained.

Wine damaged by excessive warmth may show cooked fruit, jammed aromas, flattened freshness or prematurely tired character. Physical signs such as seepage, a displaced closure or a sticky capsule can support a diagnosis of heat damage when they accompany the sensory signs. Exposure to air cannot reverse freshness already lost through damaging storage conditions.

A wine that is merely warm in the glass should not be diagnosed as heat damaged. Serving temperature changes perception at the time of tasting, while heat damage is deterioration that occurred during storage or transport. VinSip's wine serving temperature guide helps distinguish a temporary serving issue from a persistent cooked or stale character.

Correct the serving condition and assess a fresh pour before reaching a conclusion. If the wine becomes fresher and more balanced at a suitable serving temperature, the original problem may have been presentation rather than storage damage. If cooked fruit, jammed character or tiredness remains dominant, heat damage becomes a more plausible practical diagnosis.

Heat damage can overlap sensorially with oxidation. A heat-damaged wine and an oxidised wine may each seem flat, browned or depleted of fresh fruit. Storage context and physical evidence help distinguish the likely cause: seepage, a displaced closure or known exposure to damaging warmth supports heat damage, while bruised-apple and unwanted sherry-like aromas can point more directly to oxidation.

The overlap does not always need to be resolved before a complaint is made. A consumer can accurately report that the bottle tastes cooked, tired or oxidised and that the closure or capsule shows signs of stress. The retailer can then assess the wine and bottle without requiring the customer to prove the complete storage history.

Storage guidance is preventative rather than curative. VinSip's guide to how to store wine explains how stable and protected conditions help limit unwanted change. Once damaging warmth has altered a wine, chilling, warming, swirling or decanting cannot reliably recreate the original freshness.

A bottle may remain drinkable despite some deterioration, but drinkability and expected quality are not the same question. A retailer or restaurant may still need to assess wine sold in a condition that prevents it from showing its intended character. Describing cooked fruit, seepage or a displaced closure is more useful than making an unsupported claim about exactly when the exposure occurred.

Wine age should not be treated as proof of heat damage. VinSip's guide to how long wine lasts explains that wine changes with time and that suitability for extended keeping depends on style, condition and storage. A mature bottle can be sound, while a younger-looking bottle can be damaged if its storage or transport was unsuitable.

Labels and appellations provide expectations about style, origin and production rules, but they do not certify the storage history of an individual bottle. VinSip's guide to wine appellations explained provides context for understanding the type of wine the label represents. Heat-damage assessment must still rely on sensory character, physical bottle condition and credible storage information.

If heat damage is suspected, keep the bottle, closure and remaining wine. Photographing visible seepage or closure displacement may help preserve the condition as it appeared when opened, while the retained wine allows direct sensory assessment. Ask the seller to examine the bottle and describe the cooked, jammed or tired character without overstating what can be proved about its history.

A persistent, recognisable wine fault is a reasonable basis for asking a restaurant or retailer to assess a bottle. AWRI's catalogue of recognised wine faults and taints provides the sensory vocabulary for reporting cork taint, oxidation, reduction and related quality problems. The strongest request identifies a specific symptom rather than stating only that the wine is unpleasant.

At a restaurant, speak to the server while enough wine remains for assessment. Describe the observable sign, such as damp cardboard, bruised apple, rotten egg, cooked fruit or a dominant vinegar-like aroma. A calm request for the wine to be checked allows staff to smell the glass, inspect the bottle and decide whether replacement is appropriate.

A restaurant tasting pour is intended to help identify bottle condition, not to guarantee that every guest will enjoy the grape variety, region or producer. A sound wine can be dry, tannic, acidic, earthy, smoky, sweet or unfamiliar. Personal dislike is not evidence of a wine fault unless a persistent sensory sign corresponds with a recognised fault or taint.

Cork taint is especially suitable for direct assessment because AWRI associates it with musty, damp aromas and suppression of fruit. State that the wine smells of damp cardboard or mouldy cloth and that its fruit appears muted. Avoid relying on the cork's appearance because the sensory condition of the wine is the relevant evidence.

Oxidation can also justify assessment when bruised-apple, stale-nut or unwanted sherry-like character dominates a wine that should be fresh. Explain the expected style and the observed stale character without claiming that every oxidative aroma is defective. Some wines are intentionally oxidative, so style remains part of the restaurant's or retailer's evaluation.

Reduction calls for reassessment after exposure to air because some reduction-related aromas may lessen. Tell the seller if the wine was swirled or poured and whether the struck-match, rotten-egg or drain-like character persisted. That information shows that the complaint concerns a continuing quality problem rather than a fleeting opening aroma.

Heat damage is easier to assess when the bottle has been retained. Seepage, a displaced closure, a sticky capsule and cooked-fruit character can be considered together. Do not discard the remaining wine or closure before contacting the seller because direct examination may be necessary.

A dominant vinegar-like or nail-polish aroma can support a practical diagnosis of volatile acidity. Lively acidity, tart fruit or a sour-edged style is not automatically a fault, especially when the wine remains clean and balanced. The issue is whether the volatile character overwhelms the intended wine rather than whether the wine tastes sharply acidic.

For a retail purchase, retain the bottle, remaining wine, closure and proof of purchase where possible. Explain the sensory symptom, the serving condition and any attempt to reassess the wine after air or temperature adjustment. A retailer has a clearer basis for assistance when the report describes a recognised quality failure instead of a general dislike.

Do not claim that sensory diagnosis answers every safety question. AWRI's catalogue classifies recognised wine faults and taints by sensory character, not as a substitute for food-safety assessment. If a bottle contains unexpected foreign matter, shows signs of tampering or raises a separate contamination concern, stop drinking it and ask the seller or an appropriate authority for advice.

Clear language improves the likelihood of a fair assessment. “The wine smells of damp cardboard and its fruit is muted” is more useful than “the wine is corked” without explanation. “The rotten-egg aroma remained after exposure to air” is more useful than “the wine needs to breathe.” The description allows another person to check the same evidence.

A return should not be based solely on tannin, dryness, sweetness, acidity, unfamiliarity or a style the customer would not choose again. A return or replacement request is better supported when a recognisable fault overwhelms the wine and prevents it from showing its intended character. Retaining the bottle and describing the sensory sign gives the restaurant or retailer the fairest opportunity to respond.