5.5. SPOTTING WINE FAULTS

The following are the faults most commonly found in wine. Look out for them, and if you detect one, be sure to send it back.

I. Cork Taint

TCA, or 2,4,6 Trichloranisole to the geeks among us, is the death of many a great bottle of wine affecting up to 5% of wine bottled under natural cork. It derives from a fungus hidden deep in the pores of the cork bark itself and is very difficult to eliminate. In high concentrations it is reminiscent of a mouldy dog wrapped in wet cardboard. Mmmm, yum. It is possibly at its most insidious, however, at lower concentrations, when it will just flatten or dull a wine’s aroma and leave it finishing short. This leads most of us to think the wine itself is bad and ensures we never buy it again – not good news for the producer.

II. Oxidation

As the name suggests, this fault is caused by excessive exposure to oxygen, either during production or from the ingress of air through the closure. It is mainly characterised by a brown tint to the wine (more obvious in whites) and a slight sherry character, sometimes with a hint of rotting apples. Traditional white Rioja often has a touch of oxidation and Tawny Ports, Maderia and some Sherries couldn’t be made without it, so it really is a double-edged sword.

III. Rotten Eggs, Hydrogen Sulphide, Sulphides or Reduction

This rather nasty-smelling fault is often found during fermentation and can be easily cured in the early stages of winemaking by aeration or the addition of Copper Sulphate. Occasionally it forms in the reductive environment of the bottle, especially those perfectly sealed under screw cap. It is highly volatile and in small doses can be removed simply by aerating the wine for a short time in a decanter. If left too long or in high concentrations it can combine with other compounds to form Mercaptans, a nasty goup of substances which are much harder to remove and have an unpleasant aroma of garlic and onions.

IV. High Volatile Acidity, Volatility or VA

A group of terms used to describe wines showing a noticeable vinegary or nail varnish aroma. The problem arrives in the form of a bacteria called acetobacter, which uses oxygen and alcohol to produce Acetic Acid, the main component in vinegar. This in turn reacts with Ethanol in the wine to produce Ethyl Acetate. While this used to be a common fault, modern winery hygiene and filtration have banished it to all but the most rustic of wines.

V. Brettanomyces or ‘Brett’

Brettanomyces is a yeast responsible for creating aromas remarkably similar to sticking-plasters, often mixed with a farmyard/animal aroma. In small concentrations this can add complexity to some red wines but it is generally considered a fault. It is harboured in used barrels, hoses and tanks and once ensconced in a winery can be very hard to remove. In most modern wineries correct hygiene and the use of sulphur dioxide is enough to keep populations under control.

VI. Deposits, Sediments and Hazes

Many wines will form deposits over time that are completely harmless to consumers and do not affect the taste of the wine. Red wines, particularly robust styles, can form a crusted, slightly crystalline deposit after aging for a few years and white wines will occasionally form crystals of potassium bitartrate that can be mistaken for glass, especially after refrigeration. Some hazes, however, are indicative of a fault. A good general rule is if a haze is accompanied by a strange and unusual smell then the bottle should be replaced.

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