Learn about Wines in Tokyo

Sunday, 10 May 2015

Common Wine Faults Explained



From the damp-cardboard smell of a corked bottle to crystals at the bottom of your glass, flawed wine can spring some surprises          

                   
I ONCE HAD a rather strange experience with a screw cap. It was the depths of winter, and I was in the mood for a glass of full-bodied Australian red. After twisting off the cap, a small plastic disk remained on top of the bottle. As I moved to pick it off, pop! Off the disk flew and wine sprayed everywhere.
I’m still not quite sure what happened. Possibly, some carbon dioxide was trapped inside during bottling, creating a buildup in pressure. Or a combination of excess sugar and a high storage temperature may have caused the wine to re-ferment. I suspect it was the latter, as the wine was fizzy and I ended up pouring it down the sink.
This explosive encounter reminded me that wine can be prey to all sorts of unexpected faults, from cork taint to small crystals at the bottom of the bottle. Some are easy to detect, clearly affecting the taste, but others are less obvious.
The most common fault is corked wine. Thankfully, with its dank, wet-cardboard smell, corked wine is also one of the easiest faults to spot. Caused by chemical compound 2,4,6-Trichloroanisole, transferred from the cork, the taint can vary in intensity from a faint whiff to a full-on moldy stench. If you're in any doubt about a bottle you’ve ordered at a restaurant, check with your sommelier, who should be happy to replace the bottle.
A wine can also smell like rubber, a struck match or even rotten eggs. This is known as reduction and is caused by sulfur compounds used as preservatives. In less extreme cases, the smell will dissipate. Master of Wine Jasper Morris taught me a trick to speed up this dispersal: Drop a copper coin into the glass and swirl it around. The copper reacts with mercaptans (the compounds that give the wine a stinky note) and helps disperse the smell within minutes.

Wine can be prey to all sorts of unexpected faults, from cork taint to small crystals

Not all faults render a wine undrinkable; some change it in a way that will appeal to certain drinkers. A wine that tastes like sherry or baked apples, for example, may be oxidized. Though this is most often caused by a faulty cork, in some cases it’s the result of a particular winemaking style.
Brettanomyces, or brett, is another fault that can be a virtue in moderation. Easy to spot, with its farmyard or earthy smell, brett is a yeast that can creep in at various stages in the winemaking process. People’s tolerance of the flavor varies. As long as it doesn’t dominate the wine’s overall character, I believe it adds a complexity and savory element.
Similarly, volatile acidity—a vinegary taste from acetic acid produced by yeast and bacteria—is hard to detect at low levels and isn’t necessarily unpleasant.
Finally, tartrate crystals, which form from tartaric acid when a wine is stored below 5°C, look like little shards of glass or tiny precious stones at the bottom of the bottle. Ignore them—they’re tasteless and don’t affect the wine’s character at all.

Source: www.wsj.com/