When Good Wines Go Bad: A Guide to Identifying the Seven Most Common Wine Faults

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Statistics suggest that one in every twenty bottles of wine produced in a single year is corked and even more have been irreparably damaged by improper handling, storage or through flaws in production. Yet many are still unaware of the numerous faults their wine may be suffering from and cannot identify these defects should they present themselves.  

Below is a helpful list of the seven most common wine faults and a guide on how to recognize them.

1 – Cork Taint (TCA):

While many wines that are “off” are described as such, a wine that is “corked” must be one that has been infected with the bacteria Trichloroanisole (TCA). TCA can develop in any organic matter, such as wine corks or barrels, and while wineries are taking steps to avoid infection, such as purchasing corks from a variety of sources and mixing different batches, cork taint is still one of the most common wine faults to encounter.

Important to note: wine bottles with Stelvin closures or screw caps can still experience cork taint!  

In what is known as systemic TCA, an entire winery can become infected by the bacteria, which can live in any organic material such as barrels or woodchips. As such, regardless of closure, any bottle of wine is susceptible.

How to identify: Aromas of moldy, wet cardboard or newspaper and a lack of fruit.    

How to prevent: Sorry, no running from this one. Once a bottle is infected, it will only get worse as time goes on.

2 – Heat Damage:

Another common fault, bottles of wine may become damaged due to excessive temperatures that can occur during storage or transportation. Spikes in temperature generally cause the cork to dry out and shrink, allowing seepage. Overly high temperatures can also result in a drop in acidity and can cause the wine to become matterized.

How to identify: Look for strong aromas of stewed or burnt fruit. Also, check the cork. If the wine has penetrated all the way through, the cork has pushed out or if there is any leakage, your wine may have been damaged.

How to prevent: Store wines in a cool, place without any temperature fluctuations or excessive humidity.

3 – Light Damage (Gout de Lumiere):

While wines are often bottled with dark tinted glass to prevent this, light can and often does damage bottles by causing a degradation of the organic compounds found in wine. And while light damage tends to affect delicate wines and white wines most significantly, all wines are susceptible.

How to identify: A weakened acidity and aromas of canned corn or cooked cabbage can reveal light damage.

How to prevent: Simply store wines in a dark environment.

4 – Vinegar Taint (Volatile Acidity):

Vinegar taint occurs when temperatures during fermentation are not monitored or when air enters into the bottle either through faulty corks or improper storage. The alcohol turns into acetic acid and the wine’s fruit flavors are overtaken with sour, vinegar notes.  

How to identify: Aromas of vinegar or nail polish remover are a dead giveaway.

How to prevent: Proper storage can help, but unfortunately once the bottle has been affected, there’s no escaping this one.  

5 – Secondary Fermentation:

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While some wines purposefully undergo a second fermentation – think Champagne and other bubbly – if your wine has unexpected carbonation, the winery may have bottled too early or bottled an unstable wine. As fermentation did not come to an end, it eventually resumes in bottle.  

How to identify: Bubbles are the main giveaway here. When you open a bottle of wine and it sounds like you are opening a soda, that’s pretty good evidence of a secondary fermentation. 

How to prevent: Once bottled, there’s nothing to be done. But make sure you are aware of the wine you are drinking. Some wines, i.e. Vinho Verde, are made in a frizzante style and some sparkle is to be expected.

6 – Sulfur:

While sulfur is often employed in the winemaking process to prevent other flaws from occurring, excessive use in the vineyard or winery can seriously damage a wine.     

How to identify: Pungent aromas of rotten eggs or burnt matches.

How to prevent: Throwing the wine into a carafe can help much of the foul odors to blow off.  

7 – Oxidation:

Acceptable in some levels – think Sherry or orange wines –but too much oxygen exposure can cause a breakdown in the color and flavor components of a wine. One of the most common flaws to encounter, oxidation is pretty easy to recognize. If you have a bottle of wine hanging around the house that’s been open for a while, take a good sniff. That’s oxidation.

How to identify: Aromas of rust, nuts or stewed fruit, browning color and a general lack of freshness.

How to prevent:  Wine pumps help preserve opened wine, but if the wine was damaged due to improper storage or handling, the fault is irreversible.    

If you encounter any of these seven faults in your wine, or even just suspect them, return the bottle ASAP. Retailers will offer a return or exchange and distributors will offer an invoice credit or replacement bottle, no questions asked.