Written by: Tim Edison

Updated on: June 12, 2022

10 Smells of a Wine ‘Gone Bad’ [Troubleshooting Wine Odors]

Does the aroma of your wine surprise you but not in a good way? There are some 'tell-tale' smells to look out for that indicate a problem with your wine. We explain them below.

smelling a bad wine

That wonderful aroma of a good wine brings with it such anticipation at the thought of next tasting it.

But sadly, even good wines can be spoiled.

There are a number of distinct smell that indicate that there is a definitive fault in a wine and it would probably be wise for you to not drink it. 

Below are the 10 smells of a wine 'gone bad'.


1. Who Smelt It, Dealt It

cracked egg
What does it smell like?  

Rotten eggs, someone passing 'wind', cowpats, or sewer.

What is the culprit?  

Hydrogen sulfide.

What does it mean?

Hydrogen sulfide is produced during fermentation if the wine yeast does not receive enough nitrogen. Nitrogen is an important nutrient, needed to give the yeast enough energy to do its job. This results in some very unpleasant aromas. Hydrogen Sulfide produces a foul smell but if left long enough, it will form mercaptans & disulfides which can be even worse.


2. Skunk!

skunk
What does it smell like?  

Skunk, burnt matches, or cat pee.

What is the culprit?  

Mercaptans.

What does it mean?

Mercaptans (thiols) are a group of smelly compounds that are produced by hydrogen sulfide. Once mercaptans are formed in the wine, they are just waiting for oxygen 'to come alive' and when they get it you're in trouble!


3. Mamma Mia!

garlic bulbs
What does it smell like?  

Smells like raw garlic or rotten onions.

What is the culprit?  

Disulfides.

What does it mean?

This happens when that group of compounds called mercaptans above, gets its oxygen. This usually happens during the end of the fermentation process. They are the final form of hydrogen sulfides reign of terror. Wines should never reach our lips with the above three in excess.



Related: Wine isn't just limited to tastes and smells. What are the other sensory characteristics of wine?


4. Put a cork in it

wine cork
What does it smell like?  

"Corked", wet moldy cardboard or musty. 

What is the culprit?  

2,4,6- Trichloroanisole

What does it mean?

The infamous, ‘corked’ aroma. This happens when naturally occurring wood fungi contained in the cork comes into contact with chlorinated phenol compounds (found in disinfectants). The chemical reaction produces 2,4,6-trichloroanisole (TCA) which dulls the flavor of the wine and produces a damp, musty aroma.


5. Off to the quack

bandaid
What does it smell like?  

Band-aid, medicinal, or "hospital" smell.

What is the culprit?  

Ethyl phenols

What does it mean?

A little yeast called Brettanocmyces. It lives on grapes and on other fruits in nature, but it loves wineries, especially…wooden barrels. If it’s still alive in the bottle wine, it will metabolize any residual sugars the wine has, and presto! You’ve got last years used sticking plaster in your wine.


6. Full of pep and... vinegar

vinegar bottles
What does it smell like?  

Vinegar (smell & taste)

What is the culprit?  

Acetic Acid

What does it mean?

Made by little bacteria called Acetobacter metabolizing ethanol, acetaldehyde and acetic acid in the presence of oxygen. Vinegar gets made is this way. Not interested in a glass of red wine vinegar with your pasta? If you can smell it, it’s gone too far.


7. Grease me up!

oil in a bowl
What does it smell like?  

Oily, fatty, overly buttery, flabby or greasy (smell & taste)

What is the culprit?  

Diacetyl

What does it mean?

This greasy, oily smell is produced mainly during malolactic fermentation. Where lactic acid bacteria attack other acids in the wine. Did you ever try an oaked Chardonnay in the 70’s and 80’s? These wines were notorious for big, buttery flavors and aromas. They have gone out of vogue now. Although they are drinkable, Chardonnay in particular shouldn't be like licking a stick of butter.


8. Cigarette?

ashtray
What does it smell like?  

Wet ashtray, burnt meat or smoked.

What is the culprit?  

Guaiacol

What does it mean?

The presence of ‘smoke’ in your white wines, or in excess in your reds, could be that the grapes have been exposed to REAL smoke. This happens when smoke from fire; i.e. forest fires, comes into contact with the grape skins. The extent of this smokiness will vary on severity to which the grapes were exposed.


9. Think different, or not...

rotten apple
What does it smell like?  

Bruised apples or dry straw.

What is the culprit?  

Acetaldehyde

What does it mean?

This happens when ethanol (alcohol) becomes oxidized. It can start to happen at any point of the winemaking process, where ethanol is present and exposed to oxygen. From fermentation, when ethanol is first produced, right up to bottling. If you can smell a sherry/apple aroma, the wine was most likely left in the air too long.


10. Don't sniff that

paint thinner
What does it smell like?  

Nail polish remover, glue, wood varnish or paint thinner.

What is the culprit?  

Ethyl Acetate

What does it mean?

Two ways. Acetic acid bacteria/lactic acid bacteria made it, or it’s the reaction between acetic acid (vinegar) and ethyl alcohol. It has been said small amounts can give the wine complexity and sweetness. But again, if the reaction from either cause; is left to occur for too long during winemaking, it will rear its head in the form of paint thinner. Not delicious at all.

About the Author Tim Edison

Although not having any formal training in wine, Tim has developed an irrefutable love of wine and interest in anything related to it ever since his late teens.

Coming from a family of wine lovers, it was from a young age that he got exposed to wine and the culture that goes with it.

Tim has travelled to dozens of wine regions across the world including those in France, Italy, California, Australia, and South Africa.

It is with great joy that he hopes to share those experiences here on wineturtle.com and take you along on the journey for a second time!

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