What is "corked"
A "corked" wine is one that has been spoiled by a cork contaminated by
"Trichloranisole", or TCA, which can be detected at concentrations of just a
few parts per trillion. It affects the wine, giving it a musty, dank, mouldy
smell and an off taste.
Chlorine solutions used to sterilise corks have been found to
encourage the production of TCA. This is the most common wine fault and can
occur at the rate of one in 20 bottles opened (not at such a high rate for fine
wines). This has stimulated the development of stoppers made from types of
plastic, agglomerate cork and even screw tops.
Cork floating in the wine does not mean it is corked. It is a sign of a dried
out cork or it could simply be that the bottle has been opened poorly. Mould on
top of the cork is nothing to worry about either.
How do you tell if a wine is
too old to drink?
Contact with air, or "oxidisation", spoils wine and is caused when a wine has
been open for too long, has an ill-fitting cork or is simply too old. It is
easy to spot; on the nose the wine will have a sherry-like smell and will taste
dull and lifeless. Red wines will be dull brown in colour, and White wines will
turn a tawny or brown colour.
Opened bottles of wine have a very limited lifespan. See Drinking Wine
FAQs for information about how long you should keep opened bottles of
Are the crystals found in
some wines harmful?
You will quite often spot clear crystals that look rather like sugar in the
bottom of a bottle or glass. Sometimes the crystals attach themselves to the
cork if the bottle has been stored on its side. They are "Tartaric Acid
Crystals" (also known as "Tartrates") and are neither harmful to the drinker or
Tartaric Acid is a natural component found in grapes, and
therefore wine, that crytalises when wine becomes very cold, or if the wine is
old. Tartrates are usually a sign of a quality wine that has not been
over-treated during vinification.
It is possible to ensure that the Tartrates do not form by
filtering the wine prior to bottling. However such aggressive filtration is a
more common practice in the making of bulk-produced wines because it can also
strip a wine of its flavour.
What does it mean when a still
wine is cloudy or fizzy?
Cloudiness usually indicates the growth of yeast or bacteria; fizziness that
the wine has undergone an unintentional second fermentation in its bottle. Both
of these are definately faults, often due to bad winemaking. It is likely the
wine will be unpleasant, albeit harmless, to drink.
What is wrong with a wine that
smells and tastes of vinegar?
The smell and/or taste of vinegar indicates that a wine has either been badly
made or the bottle has been open for too long and has been attacked by a
bacteria, called "Acetobacter". Acetobacter reacts with oxygen and this
reaction changes the taste of a wine to a vinegary flavour. In fact, this is
how vinegar is made. This fault is also described as "volatile".
Why do some wines smell of "struck
Sulphur Dioxide (SO2) is the most common chemical used in winemaking. Almost
every wine is made using this compound because it helps prevent oxidisation and
stabilises wine. Careful winemakers use it judiciously because excessive
amounts of SO2 causes disagreeable aromas in the wine.
Within the EU there are maximum permitted levels that may be
used. SO2 is detected by a smell reminiscent to struck matches or bad eggs and
may cause an unpleasant tingling sensation in the nose. However these wines
will not be harmful, just unpleasant.