7 Wine Faults and How to Sniff Them Out

Wine faults ruin pretty wine
Wine faults ruin your night.

The 7 Main Wine Faults

As wine drinkers we consume a lot of flawed wine without even realizing it. Nothing to be ashamed of because most of us just don’t know what wine flaws are.

The good news is, the majority of wine faults are not bad for us. They just taste bad. So, here’s a short primer on the most common flaws in wine and how to sniff them out.

(For you wine geeks, be sure to check out the book recommendation at the bottom for more!)

Oxidized Wine

  • What it is: Contamination caused by too much oxygen exposure. You know when you leave a sliced apple out on the counter and it turns brown? It’s that same process but in your wine. Oxidization is the most common wine fault in older wines and is easy to replicate at home with any bottle of wine.
  • How you can tell: Oxidized wines lose their brightness, both in color and in flavor. Deep reds turn to a brownish-orange color, and have a strange vinegar-and-caramelized-apple characteristic.

    By the way, white wines are much more susceptible to oxidization than reds, because reds’ higher tannin levels act as a buffer. If you really want to see what this looks like: open a new bottle, pour a glass and save that bottle for about a week. Congrats, you just ruined your wine. Drink some and compare it to that first glass you had.

  • Can I fix it? No, but you can prolong the shelf life of opened wine by using a wine preservation tool. If the bottle is oxidized right off the shelf, it either had a faulty closure or was mishandled in transport. Take it back!
Wine that has gone bad, part of Rudy Kurniawan's Collection
The browning in these wines suggests they suffer serious oxidation problems. This is a photo of bottles seized from the wine forger, Rudy Kurniawan.

2,4,6-Trichloroanisole (TCA) …aka cork taint

  • What it is: A chemical contaminant that found its way into your bottle somewhere in production, usually by way of the cork. TCA can be present in oak barrels, or the processing lines at the winery as well, which leads to entire batches, rather than single bottles, being ruined.
  • How you can tell: Cork tainted wines have a dank odor that smells almost exactly like wet newspaper, moldy cardboard, or wet dog. As far as taste goes, corked wines have very little fruit flavors and be dominated by these aforementioned off flavors.

    Some estimates have placed TCA-affected wines as high as 2% of all wines bottled under real cork, making it the second most common wine fault.

  • Can I fix it? The old Saran Wrap formula, polyvinylidene chloride (PVDC), created in 1933 by Dow Chemical chemically binds with TCA taint and removes it from wine. That said, Saran is now produced with polyethylene which doesn’t have the same effect! Your only option is to return the bottle.
wine-flavors-sulfur-compounds
Learn more about aroma compounds in wine.

Sulfur Compounds

  • What it is: Sulphur is a complicated issue in wine. Sulfur is added in small amounts to almost all wine to stabilize it. Another sulfur compound found in wine called dihydrogen sulfide (H2S) is a naturally occurring bi-product when fermentations are stressed.

    Sulfur compounds smell smoky like a struck match or cooked cabbage. Most of these smells burn off in about 15–20 minutes after opening a bottle. (This is why decanting wine is handy!)

  • How you can tell: The most frequent manifestation of a sulfur-related flaw is called mercaptan (it’s related to dihydrogen sulphide). If you notice rotten egg, fart, burnt rubber, cooked garlic, or skunk smells in your wine after decanting it for some time, then you probably have a mercaptan problem.
  • Can I fix it? Decanting reduces the offending flavor (watch how to do it here). Also, stirring your wine with silver is noted for reducing the size of these large sulfur compounds (making them less detectable). Although, if it’s very aggressive, you should absolutely consider returning the bottle.

 

Secondary Fermentation Bubbles in a non-sparkling wine!

  • What it is: Tiny bubbles in your wine where there shouldn’t be any, especially in a young bottle of red wine. This usually happens when the wine is accidentally bottled with a few grams of residual sugar and then re-ferments. This most frequently occurs in low-intervention winemaking when no sulfites are added.
  • How you can tell: Look for bubbles or listen for the psssst. Wines usually smell yeasty. They taste zippy.

    Not all secondary fermentation is on accident though. Some winemakers embrace it to add a little kick to their wines, and some traditional styles of wine are naturally frizzante such as Vinho Verde, Italian Bonarda (a red), and some Grüner Veltliner.

  • Can I fix it? No, but do some research into the style to make sure it is not supposed to be there. Throw the wine into a decanter-type vessel and shake the the living hell out of it to get rid of the bubbles as well.

 

Heat Damage …aka cooked wine (“madeirized” wine)

  • What it is: Wine ruined by exposure to too much heat. Imagine a pallet of wine cases cooking in the sun in the parking lot behind a wine store in Phoenix, AZ. Yep, this happens more commonly than you might think!
  • How you can tell: The wine smells jammy: sort of sweet, but processed. The smell is somewhat like a wine reduction sauce, mixed with a nutty, brown, roasted sugar-type aroma. Heat damage often compromises the seal of the bottle (the expansion from the heated air pushes the cork out) so it can be accompanied by oxidization.
  • Can I fix it? No, but you can store your wine at the proper temperature and ensure you are not the problem. 55 degrees is pretty well accepted as the best cellar temperature. The most important part of storage is a consistent temperature. Be mindful of how hot your garage gets in the summer if that’s where you store your wine. Don’t store wine in your attic.

 

Wine and Cheese Pairings

Wine and Cheese Pairings

Our favorite wine and cheese pairing recommendations on a beautiful print.

Buy Poster

UV Light Damage …aka lightstrike

  • What it is: Damage caused by exposure to excessive radiation, usually UV. Most commonly from storing wine in the sun or near a window.
  • How you can tell: Lightstrike occurs more commonly in delicate white wines like Champagne, Pinot Grigio, and Sauvignon Blanc. It makes the wine smell like a wet wool sweater!
  • Can I fix it? No, but you can be smart about storing your wine out of direct sunlight. The colored glass of wine bottles is supposed to mitigate lightstrike; so if you get a homemade white wine in a mason jar, put it in the darkest corner of your cellar.

 

Microbial and Bacterial Taint …aka I think there is something growing in there

  • What it is: Many microbes live during the wine fermentation in addition to yeast. If one of these colonies becomes too aggressively present pre- or post- alcoholic fermentation, you can start to get various off aromas. In small amounts, they add appealing complexity, but if the colony becomes too vigorous, these flavors are considered faults, like too much salt in a dish.
  • How you can tell: Again, there are many other bacteria involved in winemaking. They impart certain positive flavors but also produce signature wine faults. For example, if your wine smells like a gerbil cage, sommeliers call this “mousy” and it’s often found in natural wines. When you try a wine and breath out and get a whiff of hay bail, this is called “ropiness” and suggests another over-productive wild microbe.

    Think of microbes like spices. In the right quantities they add an appealing complexity but too much overwhelms the wine.

  • Can I fix it? Unfortunately, no. Once it’s in there, that’s what you’ve got! Grab the microscope and go exploring!
Join Wine Folly - the free weekly newsletter that educates and entertains. Your trusted wine resource.

At least there's honesty in labeling

Not All Wine Faults Are Actually Wine Faults

Volatile Acidity …aka Acetic acid

What it is: This can be one of the most common wine faults, known as vinegar taint, but it is also a tool used by some high quality winemakers to develop complexity in their flavor profiles.

Very high levels of acetic acid smell like balsamic vinaigrette. In other words, some vinegar taint is on purpose and that style just isn’t for you. Some is a winemaking fault; an accidental process caused when fermenting very sweet grapes.

Tartrate Crystals …”glass” shards

What it is: These are mineral precipitates that form out of unfiltered, high mineral wines. They are little crystals sitting on the bottom of older bottles. Don’t worry, they won’t cause you harm, so long as you don’t cut yourself on them (just kidding!). All you need to do is decant the wine with a filter and leave the sediment in the bottle.

Herbal Aromas smells “green” 

What it is: Herbal aromas are typical parts of certain varietally-specific flavor profiles that can smell of grass, eucalyptus, or asparagus. The most common of these chemicals is methoxypyrazine or “pyrazines” for short, which are commonly found in Bordeaux-family grapes. To new or unfamiliar wine drinkers, these aromas can seem similar to sulfur or microbial wine faults but they’re not!

We recommend trying a lot of wines to learn the difference! Chin chin!

Brett smells “like a farm” 

What it is: Brett is short for Brettanomyces which is a type of wild yeast that is very odiferous! Bretty wines smell like farm yard, hay bails, sweaty saddle, Band-Aid, or “horsey.” Even in very low amounts, Brett often gives wine a metallic taste on the finish.

Despite how horrible this might sound to you, Brett is a wild thing that is loved for creating complexity. It’s certainly not okay in some wines (such as white wines or Pinot Noir), but in Cabernet Sauvignon, Syrah, or Carignan, it adds interest. Some of you love it, others hate it. But there’s no denying that Brett will be a thing in wine for years to come.

The Tools of The Trade

The Tools of The Trade

Everything you need to start drinking better wine.

Learn More

About Madeline Puckette

James Beard Award-winning author and Wine Communicator of the Year. I co-founded Wine Folly to help people learn about wine. @WineFolly