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Winemaking
Grapes are made into wine in various
ways. The three basic methods vary according to the color and type
of wine desired:
White wines
In the case of white wines the juice or free-run must extracted from the pulp
is separated from the skins (whether light or dark) before fermentation begins.
Avoiding contact with the skins means the wine takes little or no color from
them.
Rosé wines
Rosé wines are made by leaving the juice on the skins of dark grapes
briefly before or during the first part of the fermentation to extract the
desired amount of color.
Red wines
In the case of red wines, the juice is left on the skins of dark grapes during
the fermentation to extract color, tannins and other substances - a process
known as maceration.
In general the modern vinification process
consists of the following stages:
- De-stemming and crushing: The first
stage is the separation of the grapes from their stems. The fruit
is then crushed or rotated in cylinders under pressure, a process
which breaks the skins and releases the juice or must.
- Alcoholic fermentation: Grape must
have two main components, water and sugar. Yeasts multiply in this
solution, consuming the sugars which they convert into alcohol, and
producing carbon dioxide - the phenomenon we know as fermentation.
It is characterized by violent bubbling and the generation of considerable
heat.
- Drawing the wine off the lees: When
the alcoholic fermentation has converted the must into wine, it is
allowed to settle so that the solid matter known as the lees collects
at the bottom of the tank. The wine is then pumped into other containers
to separate it from the lees.
- Malolactic fermentation: Most red
wines, as well as some whites, undergo an important secondary fermentation
induced by bacteria rather than yeasts. The process is much gentler
than alcoholic fermentation and often is only made apparent by the
small bubbles which rise to the surface of the wine with a soft buzzing
sound. This malolactic fermentation transforms sharp-flavored malic
acid into softer lactic acid, lowering total acidity and giving wines
rounder and fuller flavors.
- Stabilizing and ageing: All wine needs
at least some period of ageing to stabilize and mature it before
it can be bottled. White wines, rosés and reds made to be
drunk young are generally stored briefly in large tanks made of glass-lined
cement, fiberglass or (best of all) stainless steel for between four
and six months. For wines of greater concentration and complexity,
whether red or white, the ideal containers for ageing are small wooden
barrels. Oak is the best material (there are drawbacks with other
types of wood). The ageing process stabilizes and harmonizes wines,
and allows the extraction from the barrel of "noble oak tannins" that
enhance flavor. Barrels allow miniscule amounts of oxygen to enter
the wine, favoring the development of complex secondary aromas, a
process known as controlled oxidation. Wood ageing may last from
around six months to three years.
- Refinement in bottle: Young wines
are usually stabilized by refrigeration and filtering before bottling
and are subsequently stored for one to three months before release.
Wood-aged wines are often fined using egg whites or protein compounds
and sometimes lightly filtered before they are bottled to remove
any suspended particles. Bottled wines are usually stored horizontally
for six months to a year before release. In the bottle, in the absence
of oxygen, a process known as reduction begins during which the color,
flavor and aroma of the wine evolve. It is in this phase that wines
develop their bouquet.
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