Ageing is a long and delicate process, the goal of which is to confer characteristics of quality to a wine that is already made. The starting point is a wine that is fit for consumption, and which has qualities that may be enhanced through ageing. It is usually applied to wines that are robust, strong and aggressive on the palate, with intense and vivid colours.
The ageing process is carried out in two phases: oxidation and reduction. The first takes place in wooden casks that allow the penetration of small amounts of oxygen, so naturally altering the chemical structure of many of the components of the wine. The second process occurs in the bottle. Because practically no oxygen enters the bottle, save a small amount that is filtered through the cork, the components of the wine react in particular ways to its absence.
a) Stage One in Ageing: The Importance of Wood
During the first stage of ageing, the wood and wine form a stable and practically indivisible partnership. The wood gives the wine its tannins and aromas and they blend slowly with the tannins in the wine. Nevertheless, a balance must be reached: if the wine remains in the cask for too long a period, the rough tannins in the wood will overcome the original aromas of the wine.
According to experts, the most suitable wood for this purpose is American or French oak, although other types of wood such as chestnut, South American beech and pitch pine are also used. The most common type of cask is the Bordelais cask, or barrica, which holds 225 litres.
The full, closed casks are placed in successive rows in a fully or partially dug out cellar area for approximately six months. The temperature in the cellar should be low and fluctuate only some 5ºC between summer and winter, while maintaining a relative humidity of approximately 75%. These conditions favour the process of slow, homogenous microoxidation while also reducing the loss of liquid through evaporation.
After the first six months the wine is moved to another cask to separate the clean wine from the residue accumulated at the bottom. This also allows the wine a certain degree of aeration.
This stage lasts for several months, until the wine reaches the desired point at which both the aromas and flavours of the wine have become homogenous. To attain homogeneity of quality, the wine in one cask is blended with other wines from the same vintage, after which it is lightly clarified, filtered and bottled.
|
