It is a truth seldom acknowledged in polite society that a glass of wine, however elegantly poured, may contain not only the fruits of the vineyard but also the misfortunes of the cellar. One is told, with an air of authority, that a particular bottle is “spoiled,” “corked,” or “over the hill,” yet the poor guest, uncertain of the precise meaning of such condemnations, can only smile weakly and pretend comprehension. It is to rescue the conscientious drinker from this unhappy state of ignorance that we must speak plainly of wine faults: their names, their natures, and the ways in which a well-informed palate may detect them.

For though it may wound our sensibilities to admit it, not every bottle is a paragon of virtue. Some wines are merely shy, some ill-bred, and some quite irredeemably wicked. To distinguish one from another is not only a protection to one’s enjoyment, but a mark of cultivation as sure as any knowledge of literature, music, or dance.

The Nature of a Wine Fault

Before we descend into the catalogue of imperfections, we must define our terms. A wine fault is not simply a characteristic one does not personally enjoy. A lady who prefers light, delicate wines may find a powerful, tannic red rather overbearing, but that does not render the wine faulty—only mismatched.

A fault, properly speaking, is a defect that arises from:

• Poor hygiene in the winery
• Unfortunate chemistry in the bottle
• The mischief of microbes, oxygen, or light
• Careless handling or storage

A fault overwhelms or distorts the wine’s intended character. It is as if a well-bred gentleman arrived at a ball in muddy boots: his natural qualities may still be there, but they are obscured by a very obvious impropriety.

Wine faults may be grouped into several principal categories:

1. Cork-related faults
2. Oxidation and its opposite, reduction
3. Microbial and bacterial spoilage
4. Sulfur-related and “matchstick” aromas
5. Faults of heat, light, and age
6. Issues of balance that, while not strictly “faults,” verge upon them

Let us examine each with the careful attention any scandal deserves.

Cork Taint: When the Cork Betrays Its Duty

Among all wine faults, none is so often whispered about at dinner tables as “corked” wine. The term does not refer to stray fragments of cork floating in the glass (though these may vex the eye), but to a specific chemical compound, most commonly 2,4,6-trichloroanisole—mercifully abbreviated to TCA.

Origin:
TCA is usually formed when natural cork or winery materials come into contact with certain chlorinated compounds. The cork, once tainted, passes its misfortune to the wine.

Aromas and Flavours:

• Damp, mouldy cardboard
• Wet basement or musty cellar
• Old, wet newspaper
• Occasionally a stale, dusty quality

The fruit aromas of the wine seem to vanish, as if embarrassed to appear in such company. The wine tastes flat, joyless, and prematurely tired.

Severity:

• Mild cork taint may be mistaken for a dull or tired wine.
• Severe cork taint is unmistakable and renders the wine undrinkable.

In well-ordered establishments, a corked bottle should be replaced without hesitation. To accept it out of politeness is a form of self-sacrifice that no one is bound to make.

Oxidation: Wine’s Slow Decline into Weariness

If cork taint is a betrayal from within, oxidation is more akin to a slow, melancholy wasting away. Wine, exposed excessively to oxygen, ages too quickly and without grace.

Causes:

• A faulty cork allowing too much air into the bottle
• Poor sealing (particularly in older bottles)
• Overlong exposure after opening
• Careless handling in the winery or during bottling

Signs of Oxidation:

• Colour shifts:
  • Whites darken toward deep gold, amber, or brown
  • Reds lose their vibrant hue, turning brickish or tawny
• Aromas and flavours:
  • Sherry-like notes in wines not intended to resemble sherry
  • Bruised apple, nutty, or caramel tones in young wines
  • Flattened, tired, and dried-out fruit

Some wines—sherry, certain oxidative whites, and some traditional styles—embrace controlled oxidation as a virtue, much as some characters in society thrive on drama. But when a fresh, youthful wine smells prematurely like a dusty attic, one must suspect that oxygen has been overindulged.

Reduction: When Wine Hides in the Shadows

If oxidation is the result of too much air, reduction is the child of too little. In tightly sealed environments, certain sulfur compounds may develop, leading to aromas that are, at best, challenging and, at worst, quite uncivil.

Mild Reduction:

• Struck match
• Flint
• Gun smoke

In some modern wines, especially certain whites, these can be considered fashionable, even desirable, like a slightly sardonic remark at a tea party.

Severe Reduction:

• Rotten eggs (hydrogen sulfide)
• Burnt rubber
• Cooked cabbage or sewer gas

A swirl of the glass, or allowing the wine a little time to breathe, may ease mild reduction. If, however, the odours remain as stubborn as an ill-tempered cousin, the wine is likely genuinely faulty.

Microbial Mischief: Brettanomyces and Other Scoundrels

Wine, like any society, may harbour unruly elements. Among these, Brettanomyces—commonly called “Brett”—is perhaps the most infamous. It is a wild yeast that, when left unchecked, may impose its own character upon the wine, whether invited or not.

Aromas Associated with Brett:

• Stable or barnyard
• Leather, horse saddle
• Band-aid or medicinal notes
• Sometimes smoky or clove-like tones

In the most delicate doses, some tasters find Brett adds complexity, a kind of rustic charm. But when it dominates, it overwhelms fruit, terroir, and winemaker’s intention alike. The wine begins to resemble a stable yard more than a vineyard, and not even the most romantic sensibility can forgive that for long.

Other microbes may cause:

• Volatile acidity (VA):
  • Nail polish remover or vinegar-like aromas
  • A sharp, prickly sensation on the nose
• Lactic spoilage:
  • Mousy, cheesy, or yoghurt-like notes in the wrong context

A small measure of VA can lift aromas and add liveliness, much as a spirited remark may enliven a conversation. Too much, however, and the wine becomes shrill and abrasive, like a guest who will not stop talking.

Sulfur Compounds: From Helpful Guardian to Overzealous Chaperone

Sulfur dioxide (SO₂) is employed in winemaking to protect wine from oxidation and microbial spoilage; it is, in general, a most useful and loyal servant. Yet if misapplied, it may make its presence too plainly felt.

Excessive Sulfur Aromas:

• Burnt match
• Struck flint, acrid smoke
• Occasionally a sharp, biting sensation at the back of the nose

Often these aromas fade with aeration, so one should not condemn a wine too hastily. A few minutes in the glass may restore harmony. If, however, the sulfurous notes persist and smother the fruit entirely, one may suspect a fault rather than a passing indisposition.

Heat, Light, and Other Environmental Indiscretions

Even the most well-bred wine may be ruined by poor treatment after it leaves the chateau—rather like a young lady of promise sent to stay with a thoroughly unsuitable aunt.

Heat Damage (“Cooked” or “Maderised” Wine):

• Caused by storage in hot conditions: car boots, overheated rooms, or direct sun
• Signs include:
  • Leaking or pushed-up corks
  • Stewed or jammy fruit aromas
  • Flavours reminiscent of baked fruit, caramel, or syrup
  • A fatigued, hollow palate

Lightstrike (particularly in delicate whites and sparkling wines):

• Caused by prolonged exposure to strong light, especially sunlight or fluorescent lighting
• Aromas:
  • Wet wool
  • Damp cardboard
  • Occasionally a slightly rancid or singed character

Such damage is not the fault of the wine’s birth, but of its upbringing. Proper storage—cool, dark, and steady—is as essential to a bottle’s character as a good education is to a gentleman’s.

When Style and Fault Begin to Overlap

There are certain conditions which, while technically permissible, may be so exaggerated as to feel like faults to many drinkers. These include:

• Excessive oak:
  • Overwhelming vanilla, toast, or coconut notes
  • Fruit buried beneath wood influence
• Overripe or underripe fruit:
  • Jammy, heavy wines lacking freshness

While these are not microbial or chemical faults in the strictest sense, they may be considered faults of judgment—analogous to a gentleman who dresses impeccably but speaks with unforgivable arrogance. The wine may be sound, yet its manners are questionable.

Learning to Recognise Faults: A Polite Education for the Palate

To discern wine faults is not a gift bestowed only upon the chosen few. It is an accomplishment any person of curiosity may acquire, with a little observation and practice.

Some practical counsel:

• Compare and contrast: Taste two bottles of the same wine when you suspect one is faulty. The difference, once noticed, is rarely forgotten.
• Trust your nose: If a wine smells of mould, vinegar, rotten eggs, or dirty stables, do not let anyone persuade you it is “supposed to be that way.”
• Allow for context: Some styles embrace certain characters (a touch of VA in traditional reds, oxidative notes in sherry). Learn the style before you condemn the wine.
• Give the wine air: Swirl the glass, wait a few minutes. Reduction and sulfur-related issues may improve with oxygen. Cork taint and severe microbial spoilage, alas, will not.

To send back a truly faulty bottle is not rude; it is merely the assertion of reasonable standards. No one is obliged to drink mould and vinegar merely to appear agreeable.

Conclusion: On the Virtue of Discernment

In the great society of wines, as in that of people, perfection is rare and flaws are many. Some are charming, some tolerable, and some quite intolerable. To understand wine faults is not to become a tiresome pedant, forever finding fault where others find pleasure. Rather, it is to cultivate discernment: to know when a wine is merely eccentric and when it is truly unsound.

Armed with the language of faults—cork taint, oxidation, reduction, Brettanomyces, volatile acidity, heat damage—you are no longer at the mercy of vague discontent. You may name what is wrong, distinguish accident from intention, and decide, with calm authority, whether a particular bottle deserves your patience, your time, and your company.

For in the end, wine is a companion at table, not a tyrant. It ought to bring delight, not resignation. And just as one learns, over time, to choose one’s acquaintances with care, so too may one learn to choose and judge one’s wines—with wit, with elegance, and with a firm, unflustered understanding of their faults.