Wine is a living matter, even once it has been bottled. As with
all living things, it evolves, and unfortunately, not always for
the better. It's best to remain indulgent and open when tasting
wines, but even so there are some defects that are difficult to
put to one side because they make the wine unpleasant to drink.
Here are a few of the principal faults that you can come across.
Before we get started, we will only be addressing some of the
faults that adversely impact tasting wines, and we will not be
talking about difference in appreciations of aroma and taste,
that remain a very personal affair. The faults we will be
examining are the ones that someone without any particular wine
knowledge will be able to identify, simply by looking at the
glass, smelling, or tasting the wine.
Identifying faults by sight
Some defects don't even need you to smell or taste the wine to
spot.
A cloudy wine for example might be a sign of a problem during
ageing, or of mould being present in the grapes at harvest time.
However, it should also be noted that all cloudy wines are not
necessarily bad. Lack of clarity could be due to tartaric
crystals or from small particles left in a wine that has been
voluntarily left unfiltered.
The fluidity of a wine is also important because a wine that is
too heavy when you swill it in a glass could be the sign of a
lack of sulphites to protect the wine. But it's difficult to
generalise too much because a sweet white wine will cling to the
glass much more than a dry white because of the different sugar
levels.
A wine can also have some greenish tinges, hinting at a lack of
maturity in the grapes at harvest time, or the presence of
vegetal matter such as leaves or stems. The green tinge in a
white wine is more visible in young wines, and becomes less
evident as the wine becomes more yellow with age. However the
chances are that the grassy taste will remain!
In still wines, a fault that is easy to spot is the presence of
bubbles which don't disappear after the wine has been swilled
around the glass or left to air for a few minutes. It could mean
that the wine has started an unwanted second fermentation after
being bottled, and most often occurs if we reduce the level of
sulphur dioxide when bottling.
Identifying faults by smell
So apart from the bubbles example, before giving a definitive
judgement on the state of the wine, you need to go further. The
next step is to smell the wine to confirm your initial
observation or to check for other discrepancies.
The easiest smell to identify is that of a corked wine. It?s
normally due to a poor quality of cork that contaminates the
whole bottle of wine. You can normally tell just by smelling the
part of the cork that was in contact with the wine in the bottle.
Instead of smelling of the wine, it has a strong smell of cork.
This smell can also result from an error in handling the wine
during the bottling process, when the bottles are laid down too
soon after the cork has been inserted. But the odour alone is
enough to spoil the pleasure in tasting the wine.
For the more accomplished wine tasters, the smell of an oxidised
wine can cause problems, but make note that it is completely
normal for some wines such as port or Jura wines. The wine
presents a maderised odour of very ripe fruit or even chard. If
it is just slightly oxidised then sometimes after opening it will
regain some of its freshness, but if some of the wine has also
evaporated, then there's nothing to be done. A wine that has
maderised has either passed its optimum age, or has been stored
in poor conditions, causing the wine to come into contact with
the air, and resulting in an irreversible bitterness.
The opposite fault occurs when you can detect that a wine has
reduced. You'll notice an odour of rotten eggs, mould, mushrooms,
sweat, or even leather. Generally, these smells dissipate once
the wine has been opened for a while. They often come from the
sulphur in the bottle or form if the wine is exposed to too much
sun light.
You might also notice other unpleasant aromas such as vinegar,
due to the wine being in contact with too much air, or a smell of
the lees, if a wine was left in contact too long with the lees
during fermentation. Other smells hint at a lack of maturity in
the grapes at harvest time, such as cat?s wee for Sauvignon or
green pepper for the Cabernets.
Identifying faults by tasting
The principal faults detected by the nose are often also found on
the palate. But there are also others that can only be noticed
once the wine has finally been tasted.
Bitterness is on example, which results from their being too much
vegetal matter in the must during fermentation, or a rotten taste
if the harvested grapes contained too much mould and weren't
sorted with enough care.
Some bad tastes herald from the containers in which the wine was
aged, for example if the wood in a barrel contained bacteria or
was not cleaned properly.
However, just to end on a more re-assuring note, even if we have
listed quite a few faults, fortunately we don't come across them
very often, and the vast majority of wines tasted will be in
perfect health. But it's always useful to be able to spot some of
these faults to better understand whether there is something
technically wrong with the wine, or if it's just one that we
don't like.
Other articles relating to wine tasting
The
fundamentals of wine tasting