Have you ever wondered why smelling wine is such an important step in wine tasting? The reason is twofold. First, much of the pleasure we get from wine is derived from our sense of smell. We use our retronasal olfaction when tasting wine, which occurs when wine blends with our saliva, creating flavor from smell molecules traveling through our nasal passageways. Secondly, smelling wine provides an opportunity to detect any wine faults which may be present.
In a restaurant setting, this is why the server or sommelier first pours just a taste of wine in your glass, allowing you to ensure the wine’s quality. So, let’s take a look at some of the most common wine faults you’re likely to encounter. If you’re unsure how to tell if a wine is bad, look out for these warning signs.
TCA: 2,4,6-Trichloroanisole – a.k.a. Cork Taint
TCA is a chemical compound which usually finds its way into wine via the cork. Consequently, this common wine fault is known as cork taint. When there’s TCA present in the wine, the bottle is often said to be corked. However, TCA can also be present in oak barrels or somewhere along the bottling line. In these cases, this compound has the potential to ruin entire batches of wine rather than just a bottle or two.
We smell the cork when we open a bottle of wine because it’s easy to detect TCA here. This chemical compound exudes aromas of wet cardboard, moldy newspaper, or wet dog. When there’s only low levels of TCA, it can be challenging to detect. Though the wine’s fruit flavors will be muted and it will seem less fresh.
If you encounter a corked bottle of wine at a restaurant, send it back and ask for a different bottle or a different wine all together. Additionally, if you’ve purchased a bottle of wine which ends up being corked when you open it at home, don’t dump out the bottle. Re-cork the bottle and take it back to the store, as they should replace it.
Reduction
If a stinky aroma of boiled cabbage, rotten eggs, or clogged drains greets you upon smelling your glass of wine, the wine is said to be reductive or reduced. This wine fault occurs when the wine didn’t receive enough controlled oxygen exposure during the winemaking process. Therefore, the wine’s molecules were unable to combine or polymerize resulting in this stinky smell.
Notably, reduction isn’t always considered a fault. A small amount of reductive notes can add character and complexity to certain wines. If the reductive notes are overpowering, aeration might help them to dissipate so you can still enjoy the wine.
Oxidation
Alternatively, oxidation occurs when the wine has been overexposed to oxygen. This wine fault is frequently a result of defective wine closures. Additionally, it might occur in improperly stored bottles in which the corks have dried up and no longer maintain their seal.
In the glass, oxidized wines look browner and more deeply colored than they should be. They’ll lack freshness and fruit aromas, exhibiting aromas of toffee, caramel, honey, or coffee instead.
Remember, certain wines like Sherry or Vernaccia di Oristano are made purposefully in oxidative styles. In these cases, oxidation is not considered a fault.
Sulfur Dioxide
Sulfur dioxide is added to almost all wines for preservative purposes. If excessive amounts have been added to the wine, a pungent smell of freshly burnt matches will be present. At lower levels, sulfur dioxide will mask the fruit aromas in the wine. Oftentimes, aerating the wine or giving your wine glass more vigorous swirls will dispel some of the sulfur dioxide.
Out of Condition
If wines have been improperly stored, they are more likely to lose their vibrancy and freshness. This can occur in storage conditions that are too hot, too bright with a lot of direct sunlight, or in variable conditions with inconsistent temperatures and light exposure. Consequently, the wines become dull and stale. Heat damaged wines might taste nutty with a roasted brown sugar aroma. The extra heat can also push the corks out of the bottle, thus breaking the seal and causing oxidation.
At this point, there’s not much you can do to save the wine. So, be sure to properly store your wines to prevent this avoidable wine fault.
Volatile Acidity
Volatile acidity is not always considered a wine fault because all wines have some amount of VA. Moreover, certain winemakers feel it adds complexity and character to their wines. VA is the result of a build up of acetic acid during the winemaking process cause by the acetobacter bacteria and an overexposure of oxygen. Yet volatile acidity is considered a wine fault when high levels are present, leading to vinegar or nail polish remover aromas. Nobody wants to drink nail polish remover, am I right!?
Brettanomyces
Brettanomyces, commonly referred to as Brett, is another wine fault that’s not always an indicator of a faulty wine, depending on who you’re talking to. It’s a type of wild yeast which gives wines barnyard, sweaty horse saddle, Band-Aid, or hay bale aromas. Again, some winemakers and enthusiasts believe Brett adds complexity to wines.
Personally, I can’t stand wines with Brett. It’s so unpleasant and completely overwhelms the other aromas and flavors of the wine. Plus, once Brett gets into the winery, it’s extremely difficult to get rid of. To save Brett-tainted barrels for future use, techniques like infrared lasers and pressurized steam vapor are needed as the wild yeast gets engrained in the wood.
So, now you know how to tell if wine is bad!
As with anything in life, practice makes perfect. The more you encounter these wine faults, the easier they will be to detect. Though I don’t wish many faulty wines upon you. Rather, I hope you’re exploring all the wonderful aromas in wine our favorite beverage has to offer!
