The 7 Deadly Wine Faults (and How to Spot ’em)

It’s been a long day.

You’ve planned a swift but tasty dinner, and all you need now is some wine to drink while you cook it. Perhaps even something to go with the dinner itself. You pop by the store, pick up that bottle of Cab you’ve been meaning to try, and head home.

A short time later, you’re bopping along to something catchy and the kitchen smells heavenly. You glance up from the sauté pan at the bottle and decide that it certainly does need to breathe a little before dinner, and that you might as well inhale some in the process. 

Splosh, splosh. The wine makes its way to your glass, and you lean in for the preliminary sniff…

Something is very wrong…

Scenario #1: Why does it smell like an old, water damaged basement? TCA is putting a damper on things.


Signs: Nothing to see here.

Aroma: Mould, wet dog, wet cardboard.

Taste: Muted fruit and an abbreviated finish.

Cause: Typically comes from the cork, but in rare cases can originate in barrels. A combination of compounds contribute to the off-putting aroma, notably 2,4,6-trichloroanisole (TCA), a metabolic product of fungi naturally present in the cork.   

Scenario #2: This supposedly sassy Cabernet Sauvignon smells more like grandma’s sherry. The wine has been overindulging in Oxygen.


Signs: Browning. More evident in whites than reds.

Aroma: Sherry, browned apples, loss of fresh fruit aromas.

Taste: Sherry, browned apples, flat, stale.

Cause: Overexposure to that indefatigable foe of preservation, oxygen. Can occur at any point during the winemaking process.

Scenario #3: You wrinkle your nose and sneeze. Sulphur overdose.


Signs: None.

Aroma: Struck match. Muted fruit. For many people it’s more of a strong tickling or tingling sensation in the back of the nose, and can even cause sneezing.

Taste: Maybe a little sulphurous, but you’ll likely feel it more than taste it. 

Cause: Normally undetectable at standard levels, sulphur dioxide is not pleasant when additions are excessive. The overdose most likely occurred at bottling.

Scenario #4: The smell of nail polish remover singes your nose hairs. VA is making its presence felt.


Signs: No visual indication. 

Aroma: Nail polish remover or vinegar.

Taste: Hard, hot mouthfeel.

Cause: A group of bacteria called acetobacter, in combination with oxygen, produce acetic acid (vinegar). When acetic acid comes into contact with ethanol, ethyl acetate (nail polish remover) is produced. Both of these are always present in wine, and inoffensive in small amounts. VA intense enough to become a fault is found where there is inadequate sanitation in the winery, damaged fruit, and/or insufficient sulphur dioxide.

Scenario #5: You’re immediately transported to your great uncle’s barnyard. Brett has taken up residence in your wine.


Signs: The stud next door paws the ground and eyes you up and down. (Kidding! None.)

Aroma: Animal, sweaty saddle, barnyard, band-aid, and antiseptic come from 4-ethylphenol (4-EP). 4-ehtylguaiacol (4-EG) is responsible for smoky, spicy, clove, and bacon aromas.

Taste: As above.

Cause: These 2 volatile phenols, 4-EP and 4-EG, by-products of the Brettanomyces yeast, create off-aromas. 4-EP’s aromas are by far the less pleasant, and when Brett is present, in moderation, in either form, it can be considered an asset to the wine, or in the case of some French wines, a vital characteristic. The cleaner the winery, the less likely the occurrence of Brett; however, once it has made its way into the winery, it is almost impossible to eradicate completely.

Scenario #6: Someone slipped a Christmas pudding into the bottle. Stewed fruits, nuts, and sherry… This wine has been cooked.


Signs: A raised cork straining against the capsule. A capsule that doesn’t turn freely against the bottle. Leakage, new or crusty, around the cork or coming from under the capsule. Brick colour in red wines.

Aroma: Stewed fruits (prunes), nutty, sherry- or Madeira-like.

Taste: Wine tastes thin, lacks body and fresh fruit flavours, and has an oxidized character.  

Cause: Exposure to excessive heat. This is a very common fault that is often not the result of a blunder by the winemaker, but rather a shipping or storage issue. Heat causes the wine to expand, pushing up the cork and seeping out, and then cools, potentially leaving openings for oxygen to get in and attack the wine. The result is a double whammy: cooked and oxidized flavours come together to make a faulty wine. 

Scenario #7: Where you were hoping for cassis, spice, cedar and tobacco aromas, you found a charming sweaty armpit-onion blend. Mercaptans are raining on your parade.


Signs: Nothing at all.

Aroma: H2S – rotten eggs; Mercaptans and Disulfides – onions, garlic, burnt rubber, and unwashed, sweaty armpits.

Taste: See above, and then hide.

Cause: A nitrogen deficiency in the fermenting must is the culprit. It leads to the formation of hydrogen sulphide compounds and, if left untreated, they react with other wine compounds to form mercaptans and disulfides. Careful monitoring of nutrient additions throughout the fermentation, and racking the wine off the yeast lees (aerating it in the process) immediately after fermentation are simple ways to prevent this problem. The more advanced incarnation, mercaptans, can be treated with a copper sulphate addition.

 Never mind. You’d rather have a martini tonight, anyway.

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