The 7 Main Wine Faults
Oxidized Wine …aka maderized wine
What it is: Contamination/chemical breakdown caused by too much oxygen exposure. Rusted metal is oxidized…it’s that same process but in your wine. Oxidization is the most common wine fault and is easy to replicate at home with any bottle of wine.
How you can tell: Oxidized wines lose their brightness, both in colour and in flavour. Bright reds turn to brick colour or brownish, and fresh tastes develop drier, more bitter characteristics. 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, your bottle is ruined. 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 preserving tool. If your bottle is oxidized right off the shelf, it was either poorly sealed or mishandled. Return it.
2,4,6-Trichloroanisole (TCA) …aka cork taint
What it is: A chemical containment that found its way into your bottle somewhere in production, usually from the wooden 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: Dank odour and taste like wet newspaper, moldy basement or smelly dog. It’s estimated that over 2% of bottles are tainted with TCA to some degree, making it the second most common wine fault.
Can I fix it? Andrew Waterhouse, professor of wine chemistry at the UC Davis, claims you can pour the wine into a bowl with a sheet of plastic wrap. The TCA will be attracted to the polyethylene and pulled from your wine. I say life is too short for fixing wine faults. Return it.
What it is: Sulfur is a common additive to wine typically used to prevent other wine faults found in this article (ironically). Sometimes things can go wrong in its deployment though, and sulfur levels that are out of whack are pretty easy to notice.
How you can tell: There are 4 primary sulfur compounds that can give your wine some funk, but they all manifest themselves in terrible flavours and smells. If you notice rotten egg, fart, burnt rubber, skunk, or asparagus pee in your wine, you probably have a sulfur problem.
Can I fix it? The offending flavour can be weakened through decanting. If it is strong though, you should send it back.
Secondary Fermentation …aka THIS IS NOT CHAMPAGNE!!
What it is: Tiny bubbles in your wine where there shouldn’t be any, especially in an old bottle of red wine. This usually happens when the residual sugar in the bottled wine feeds some critter introduced in unsanitary bottling.
How you can tell: Duh, look for the bubbles or listen for the psssst. There can also be a bit of a zippy flavour. Not all secondary fermentation is on accident though. Some winemakers will use it to add a little kick to their wines, and some styles are naturally frizzante such as Vinho Verde or some Gruner Veltliners.
Can I fix it? No, but do some research into the style to make sure it is not supposed to be there.
Heat Damage …aka cooked wine
What it is: Wine ruined by exposure to too much heat. Imagine a pallet of wine cases cooking in the sun in a car park behind a wine store in Spain in the middle of summer.
How you can tell: The wine smells jammy: sort of sweet, but processed. The smell reminds me of canning or making wine sauce. 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. 10-12 degrees Celsius is pretty well accepted as the best cellar 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!
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 is most common in delicate white wines like Champagne, Viognier, and Chenin Blanc. It can make the wine taste like a wet sweater.
Can I fix it? No, but you can be smart about storing your wine out of direct sunlight. The coloured 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 Taints …aka I think there is something growing in there
What it is: Could be lots of things. Remember that wine is a product of microbial activity, and a lot of the handling of the wine in production is to make these microbes as happy as clams. There can be rogue strains of yeast that hijack the wine, or foreign critters that evaded sanitization.
How you can tell: Again, there are many bad guy bacteria out there. They all impart certain flavours and produce signature wine faults that fancy-pants Sommes brag about being able to distinguish, but mostly the bacteria all spoil the wine. They can have medicinal (think band-aid or rubbing alcohol), animal (think rodent cage or barnyard), or microbial (think yeasty sour things) flavours that are all pretty nasty.
Can I fix it? No, that flavour is either the critters themselves or their poo. Grab the microscope and go exploring!
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 flavour profiles. Very high levels of acetic acid taste like stomach acid…but tastes vary from one wine drinker to another on how much is too much in the wine. In other words, some vinegar taint is on purpose and that style just isn’t for you. Some is a wine making fault; an accidental or inadvertent overdose of acetic acid.
Tartrate Crystals …aka 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. They will cause you no harm. Just decant the wine leaving the sediment in the bottle.
Herbal Aromas …aka smells weird
What it is: These are purposefully developed, varietal specific flavour profiles that can smell of grass, eucalyptus, or asparagus. To new or unfamiliar wine drinkers, these aromas can seem similar to sulfur or microbial wine faults. Try a lot of wines and you will get better at tasting the difference. Chin chin!
Credit to http://winefolly.com/tutorial/wine-faults/ for this helpful article.