Nose can detect most wine defects

by Lorri | Feb 29, 2012 | UnCorked

Judging the quality of a wine is essential to its enjoyment, and understanding quality starts with a simple question: Does the wine smell clean? Whether you are a beginner or expert, your nose will quickly guide you.

Twenty years ago, poor quality, unclean wines were more commonplace, but with today’s technology only a minuscule amount of bottles are faulty because of an error in the wine-making process. A modern wine that is in good condition will not have even a slight smell of musty basements, mold, rotten eggs or vinegar.

If you do detect one of these aromas, the culprit, most likely, is the cork or improper storage conditions along the journey from the winery to your glass. Following are some common problems and ways to identify them.

CORK TAINT/CORKED WINES

Corked wine, or cork taint, as the flaw is also called, is one of the most obvious defects. The wine will exhibit musty aromas like a moldy, damp basement or wet cardboard and newspapers. Cork taint is the most common wine fault and is thought to affect up to 10 percent of all wines bottled in the world.

Taint is caused by cork infected with a fungus producing 2,4,6-trichloroanisole (TCA). When this chemical comes in contact with the wine, it imparts musty and moldy aromas. Research suggests there may be a connection between the process of chlorine bleaching the corks and the development of the fungus.

In the late 1990s cork taint forced many wine producers to seek alternate closures, including screw caps and synthetic corks. Because the TCA fungus is not able to harbor in screw tops, crown caps or other noncork closures, they are safe alternatives for avoiding faulty wines caused by an unlucky draw of a tainted cork.

OXIDATION

Oxidation is the result of a wine being exposed to air and is usually caused by a faulty cork.

Oxidized wines are simple to detect, with dull or stale fruit aromas and flavors. These wines will have a brownish color because of the contact with oxygen, much as a cut apple will brown when exposed to air. Keep in mind a few wines are intentionally oxidized during the making, such as sherry and port. But for the others, oxygen is not a wine’s friend, either in the bottle or during wine making.

VOLATILE ACIDITY

Though rare in commercial wineries, volatile acidity occurs from poor hygiene or prolonged undesirable temperatures during winemaking. It is more common for home winemakers. Volatile acidity is most often caused by bacteria in the wine, creating acetic acid. It is most easily recognized by the aromas of vinegar or nail polish remover.

BAKED WINES

Baked or cooked wines are largely due to exposure to high temperatures during storage or transportation. Not only does the extreme heat change the taste of a wine, but it can also cause oxidation. When a wine is exposed to high temperatures, the liquid expands, forcing the cork from the neck of the bottle. After the wine cools, the cork will contract, leaving the opportunity for air to trickle in around the displaced cork.

Detecting a cooked wine is straightforward because it simply tastes and smells as if the wine was cooked. The wines usually lose freshness, smelling more like stewed fruits or prunes.