If you smell wet dog, old socks or moldy basement, you may be experiencing cork taint or the presence of TCA. Trichloroanisole. Recent studies argue that the cork contamination affects less than 1 percent of all wine bottles. The production of TCA in cork or its transfer by other means in to wine is complex, but most results when naturally-occurring airborne fungi are presented with chlorophenol compounds, which they then convert into chloroanisole. Chlorophenols taken up by cork trees are an industrial pollutant found in many pesticides and wood preservatives, which may mean that the incidence of cork taint has risen in modern times. Ironically, chlorophenols can also be a product of the chlorine bleaching process used to sterilize corks; this has led to the increasing adoption of methods such as peroxide bleaching.
Brettanomyces, also know as Brett, can be a wine’s worst nightmare. Brett is a yeast species that contaminates wine and damages the fermentation process. Brett can become evident in flavors described as manure, sweaty farm animal, Band-Aid and burnt plastic. At low levels it can offer spicy characters, but as the levels increase it can ruin a wine.
Can lighting affect wine taste? One German study found that drinkers who were served a bottle of Riesling in differently lit environments had different taste experiences. Researchers found that subjects rated the wine as better and more expensive tasting when exposed to the red or blue background lighting versus rooms with green or white background lighting. According to an article in the Telegraph, the wine was described as being sweeter and fruitier in red light than in white or green light. When drinking in the red or blue lit room the subjects though the wine was worth as much as one euro more for the same bottle.
Dr Daniel Oberfeld-Twistel, of the Johannes Gutenberg University of Mainz said in the Telegraph article that more tests are needed to determine why the color makes a difference. One theory is that some colors put people in a more positive mood but it may be more complex than that. The study certainly makes a case for mood lighting in wine shops and tasting rooms as well as in bars or restaurants.
The problem with identifying wine faults such as cork taint, oxidation, sediment and tartrate crystals or brettanomyces (a subject I will return to later) is that more often than not there is no fault with the wine at all. It just doesn’t taste quite how the drinker expected it to. Take our “earthy” Italian wine. If one is used to a softer, approachable, supple form of wine such as an Australian Merlot instead of the bitter, tannic and dry flavor of an Italian grape variety such as Nebbiolo, then naturally the Italian wine can come as a bit of a shock to the palate.
Similarly, when a wine is served with small pieces of cork floating inside the glass, it isn’t actually corked, it is just that the cork has crumbled and fallen into the glass. These may seem basic rules to some but I wager right now there is someone beckoning the sommelier over, arguing that there are small bits floating on his wine and he will under no circumstances drink “corked wine.”
So how does one identify corked wine? Firstly, it is worth pointing out that in the U.K. this is becoming less of a problem as more wine producers are reverting to screwcaps. Unfortunately for those wines bottled with a cork, there are still corks that are contaminated with TCA, a chemical compound 2,4,6-trichloroanisole that gives the wine an unmistakable pungent, mouldy odor.
By far a more common fault, in my experience, is the wine that has been ruined through oxidation. This is when a small amount of air has seeped in through the cork, leaving the wine smelling “sherried” or without any discernible fruit characteristics. Rarer these days, but still prevalent in some wines, is the occurrence of opening a bottle to find it is “off,” displaying a foul-smelling nose. When I worked in the wine trade a few years back, I learned that this was because of the wine being contaminated by bacteria left over in the winery.
Sediment collected at the bottom of a wine glass can be unpleasant to drink but is entirely natural and expected in wines that are aged. Decanting the wine should avoid this experience. Small tartrate crystals that appear in white wine are also nothing to worry about; they form naturally in the winemaking process.
One fault beloved of wine snobs is that of “brett,” or brettanomyces, to give it its full name. Hugely controversial, brett is a yeast that imparts a distinctive flavor to a wine, best described in my experience as a sort of smoky bacon flavor. It is found predominantly in red Bordeaux, and for many the taste actually improves the wine, adding complexity and character. Those who don’t like the taste, and there are many, often say that it is a result of bad winemaking.