Wine barrels

Wine barrels await their fate. Wines often get a shot of sulfur dioxide when going from barrel to bottle, but too much can lead to an unwanted taste in some cases.

”Oh how blest for bounteous uses is the birth of pure wine juices!

Safe’s the table which produces wine in goodly quality.

Oh, in color how auspicious! Oh, in odor how delicious!

In the mouth how sweet, propitious to the tongue enthralled by thee!”

— Translation of 12th Century “Latin Song of Wandering Students”

Written almost 1,000 years ago, these words still ring true.

It’s as easy now as then to find pleasure in wine, and pleasure is what we all look for every time we pull a cork. But in order to be a better taster it’s absolutely essential to understand wine flaws.

Learning to identify bad bottles — whether they’ve been damaged by a tainted cork or barrel, a rogue yeast or some other biologic fault — will separate them from those that are perfectly sound but simply don’t fit your personal taste.

Without having to dive too deeply into chemistry, anyone who enjoys a good glass of wine can learn to spot the most common problems. Here are four of them.

Corked wine

This is one of the more confusing terms as it is often tossed out as a general critique. But it’s also one of the easiest flaws to spot.

The odd habit of sniffing the cork relates to this problem, which can often result from a cork tainted with a chemical whose shorthand name is TCA. The cork will have a strong musty odor, something like wet cardboard, or the drawer of an old dresser in your grandmother’s attic.

Though harmless, it can all but obliterate the fruit flavors in the wine, leaving it rather flat and yes, musty.

TCA can also result from tainted barrels, or even from the winery building itself if its wood has been treated with chlorine or bleach. Whatever the source, it may occur at very low levels that are barely perceptible, or it may be overwhelmingly obvious.

The recent interest in alternative wine closures is largely the result of the corked wine problem.

Somewhere between 2% to 5% of all wines bottled under natural cork have been found to contain some level of TCA, and once a consumer has tasted just one bad bottle they might well conclude that they don’t like that particular wine. So that one bad bottle can cost a winery a customer for life.

If you are uncertain about whether a wine is corked, pour it into a glass and wait an hour or two. If TCA is the problem, it will get worse over time.

Though there are many theories about how to “fix” such wines, I’ve yet to find one that works. Dump it and move on!


While there isn’t anyone who likes TCA, brettanomyces — commonly called “brett” — has more than a few fans.

It’s your nose once again that will alert you to its presence. If you smell tack room leather, chicken yard compost, or medicinal band-aid aromas, you’ve probably got a brett-infected wine.

Again, this is not dangerous. For some tasters, brett can add interesting scents and flavors to robust red wines. However, too much will deaden the fruit and dry the wine out, so that even a young wine with excessive brett will taste thin and leathery.

This is a type of yeast that can actually bloom in the bottle, so a wine that is only mildly affected at first may get worse and worse over time. Should you come across a wine with an unmistakable leathery scent and deadened fruit flavors, there is nothing you can do to fix it.

Volatile acidity

Volatile acidity — or VA — gives wines a high-toned pitch, which is not necessarily bad. However, if a wine smells vinegary or like nail polish or glue, that’s too much.

This is one area where it helps to know your own palate. Some people — and I am one — are very sensitive to VA and can tolerate very little. While for others it takes a much higher concentration to have any impact.

Sulfur dioxide

Sulfur dioxide is often blamed for causing hangovers, and for some people that may be true. But it’s also essential for preserving and protecting wines from premature oxidation, re-fermentation in the bottle, and other bacterial woes.

Most wines are given a dose of sulfur dioxide when they are bottled.

Too much sulfur dioxide can smell like a burnt match, and other sulfur compounds can lead to unpleasant smells like rotten eggs or rubber tires. Oftentimes simply decanting or aerating the wine will fix the problem.

With these helpful tips on sulfur dioxide, VA, brett and TCA, you should be able to spot some common wine flaws.