Bad Wine

Learning what wine flaws smell like


There are many potential flaws in bad wines, and the sad part is that, more often than not, a bad wine's flaw is so subtle that it ruins our experience without us even knowing -- well, almost. Most of the major flaws found in a bad wine are pretty distinctive, and getting to know them can help you separate the good wines from the bad wines.

It would be great for everyone involved if we all could tell a corked wine from a truly bad wine, and knowing the difference can end up saving you money whether you are returning a bottle out on the town, or bringing it back to a retailer. Get to know what’s wrong with your wine! Learn about bad wine!


Corked wines, or wines affected by trichloroanisole (TCA), are the biggest problems in the world of wine. The level of TCA is what can be the issue, ranging from barely perceptible to overwhelming.

When it’s really obvious, corked wines smell of moldy newspapers, damp socks, mold and mushrooms (though many old wines develop that mushroomy aroma naturally). When it’s below our level of detection TCA still can crush a wine by stripping it of its fruit, leaving it out of balance and shrill.


Brettanomyces is the by-product of yeast activity in a wine, though not the good yeast that converts sugar to alcohol. It is usually present in oak barrels, though it does infect entire cellars, and is mostly closely associated with the wines of the Southern Rhône and to a certain extent, Tuscany -- though it can, and does, appear in every major wine-producing region.

In low concentration Brett can add great complexity to a wine’s bouquet. The typical positive descriptors tend to be a little funky, like barnyard, horse blanket, horsey, sweaty and/or cheesy. In higher concentrations, the aromas of Brett are typically created by three distinct chemical compounds, one of those -- 4-ethylphenol -- smells exactly like Band-Aids!


As wine ages, it oxidizes. Just like iron rusts, oxygen converts certain compounds in wine into other, generally less desirable compounds. At a slow controlled rate this creates the complexity of aged wines. When a wine is too old, or has been exposed to too much oxygen either through a faulty closure or too much time in barrel, the aromas and flavors of an oxidized wine tend to recall toasted nuts, brown spices, and other tan flavors.

Oxidized wine is often referred to as Maderized. Madeira is a famous wine that undergoes an intentionally oxidative winemaking process, giving it a unique flavor profile and the ability to age nearly forever.


My wine is reduced -- what the heck? Well, just as a wine can be faulty if it’s exposed to too much oxygen during the winemaking process, a wine can be faulty if it’s exposed to too little as well! Without oxygen being introduced during the winemaking process, hydrogen atoms end up bonding with sulfur to produce hydrogen sulfides, which smell like rotten eggs.

If not dealt with, these hydrogen sulfides can combine with carbon atoms in the wine, resulting in skunk and rotten cabbage aromas.


Since we’re on the subject, it’s worth noting that there are sulfur dioxide aromas in wine that are a different class of fault than the hydrogen sulfides of reduction. Sulfur dioxide is easily recognizable as a sulfury (duh!) or struck-match aroma.

It’s worth noting that sulfur, used as an antioxidant and preservative in wine, is very common. Some producers now make wine with no sulfur added, and while these tend to be very expressive wines, they are also very prone to having bacteriological and re-fermentation issues in the bottle, which lead to whole slew of other faults.

Volatile acidity

This one is a bit of a doozy. First off, a little bit of VA, as volatile acidity is referred to, can really make a wine’s bouquet explode with intensity and depth, so a little is usually good. VA comes in two main forms: the first version is acetic acid, and gives wine a vinegary smell.

Over time, the acetic acid interacts with the alcohol and creates ethyl acetate, which smells just like nail polish remover, mostly because it is found in most nail polish remover! Now, I wouldn’t go around drinking nail polish remover -- that would be very bad -- but you don’t have to worry about drinking wines that exhibit this form of VA. In fact, many of the greatest dessert wines ever made exhibit noticeable VA!

Our Favorite Aromas

After all this talk about off aromas it's time we take a look at some of our favorite aromas, why they occur, and which wines we can find them in.

Read - Wine Nose for all the details

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Mentioned in this article


  • Thank you for your daily articles. There are times when I would like to print the entire article for reference later. Is it possible to do that without having to copy each section?

    Oct 20, 2010 at 1:12 PM

  • More often THAN not ... sheesh

    Oct 20, 2010 at 4:52 PM

  • Snooth User: Wyverrn
    537756 5

    I would imagine not, because you you won't get to see all the advertisers...still well worth it though.

    Oct 20, 2010 at 5:16 PM

  • Snooth User: Bigguy49
    573758 2

    I have also complained about the "Powerpoint" method of presentation on another one of the threads but it did not garner any response. My guess is management DOES NOT read the responses. I too like to print for reading at leisure. Maybe you can print the full article if you work your way to the end of the presentation.

    Oct 20, 2010 at 5:33 PM

  • sometimes a wine is very corked initially. Then after a while the corkeffect is gone (at least the detectable part of it) how can that be possible ?

    Oct 20, 2010 at 5:46 PM

  • Great article that takes kind of techie jargon and makes it quick and easy to understand. This was a nice brush up on the different faults for me, too.

    Oct 20, 2010 at 5:53 PM

  • Snooth User: parksl62
    616972 1

    I really love your daily news articles, they are concise, efficient and informative! I would really like to be able to print these out for future reference, but there doesn't seem to be a way to do this, do you think that will be possible in the future sometime soon?! Thank you.
    Linda, Portland, OR

    Oct 20, 2010 at 8:09 PM

  • great article!

    Oct 20, 2010 at 8:33 PM

  • Snooth User: ehguy11
    214073 25

    The strangest aroma I ever got from a bottle of wine was of strong hair dye! It was a Spanish red. Nasty aroma, but it dissapated somewhat after about an hour and we drank it.

    Oct 20, 2010 at 8:48 PM

  • For some of us urban dwellers, analogies with horses and skunks are a little challenging.

    As with positive elements of a bouquet, could future analogies be a bit less rural?

    Now, excuse me while I seek treatment for my nose, injured while trying to detect the fragrance of a struck match...

    Oct 21, 2010 at 10:58 AM

  • Am I the only one who noticed the grammatical error in the very first sentence of this article: "...more often THEN not..."? Seriously, if you're going to write for a living, please learn the difference between "than" and "then". You lose all credibility right off the bat with such errors.

    Oct 21, 2010 at 12:48 PM

  • Snooth User: johnmmoore
    170772 16

    The question from thomashedstrom is a good one - basically how an off smell can be detected but then seem to disappear. There is a fancy word for this that escapes me, but the olfactory can acclimate to a smell, sometimes quite quickly for some scents, and cease to detect it. I had this demonstrated with a corked bottle - very obvious on the first whiff, but then harder to pick up on the second and third. And I only noticed a strong Brett (bandaid) smell in a Pinot after the second glass - maybe as it opened up, the Brett bouquet became elevated. And, of course, detection levels vary among people, and some flaws, like TCA, are much more obvious in some wines (e.g. Riesling) than others. Taber's "To Cork or Not to Cork" is a deep dive into wine closures, and he hits on several flaws in wine including TCA, reduction, Brett, etc.

    Oct 21, 2010 at 4:12 PM

  • Snooth User: imasngr
    530493 3

    Love the pictures, esp the horse and skunk.

    Nov 13, 2010 at 3:06 PM

  • The easiest way to tell whether a wine is corked is to detect whether it smells or tastes of cork. You can usually tell by sniffing but either way, this is why the sommelier offers you a taste of the wine before he pours it. Once he's opened the bottle, he's not offering you the opportunity to check whether you've made the right choice between a '74 and a '93, both 'good years' according to the internet page on how to order wine that you looked up before leaving the house. The idea that more than one person in a 100 will have the faintest idea what he's doing in choosing from a wine list of names he doesn't recognise is ludicrous. Buy a wine you can afford (it'll be hugely marked up anyway). If you want to drink red with fish or white with your burger, go ahead. Either way, you have to drink what you chose if it ain't corked, even if your date is wrinkling her adorable nose because of some other perceived defect. You can get advice on what is sweet and what is dry but basically, the quality of your bottle of wine is like the chef's food - pot luck. Bon appetit.

    Oct 04, 2012 at 2:51 PM

  • Snooth User: dan545
    1154999 18

    so what are the tips? Don't drink stinking wine? Think I could have worked that one out

    Nov 01, 2012 at 12:14 PM

  • Snooth User: Steve Mirsky
    1105166 260

    When the cork crumbles as you're twisting the corkscrew, don't necessarily write off the wine inside. My first impression was yuck! But let it breathe & try it's definitely yuck or closed

    Mar 13, 2013 at 9:04 PM

  • Snooth User: Richard Foxall
    Hand of Snooth
    262583 4,003

    Skunky smells can also be compared to very pungent marijuana buds, for those of you in urban areas... although my particular urban area has no shortage of skunks, either.

    And while I agree that Greg's copy should see a copy editor besides himself (everyone should have someone proofread them if they are writing professionally), he's writing about wine, not composing a style manual, so let's not say he loses all credibility. Sounds like something a troll from another site might write. Anyone want to trace that TCP/IP address?

    Mar 14, 2013 at 4:50 PM

  • Wine enthusiasts should learn first-hand about "corked" early in their wine careers so that they can recognize it immediately and reject the bottle. Unfortunately, that is tough to do, unless a known corked bottle is presented. I have tasted two identical bottles of one-year old wines from a California winery that I know well and respect, only to have the first smell terrible while the second was excellent. Some tasters would never get past the first bottle and would label the whole winery as terrible.

    I have also tasted wines (at a Mendosa bulk winery) where ALL qualities suffer from an objectionable odor, obviously from the huge casks that they use for all their wines. (The only difference in qualities is the time in the cask, No barrels are used! They clean the casks every five years!!)

    I recommend further reading in "The Oxford Companion to Wine, 3rd Edition ".

    Aug 03, 2013 at 5:32 PM

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