Agriculture Reference
In-Depth Information
Other Methods of Red Wine Production
Fermentation on skins is the most traditional and still the most widely-used method
for making red wines in most areas. However there are two other methods also
worthy of mention.
Carbonic Maceration
The most notable usage of carbonic maceration is in the Beaujolais area of Southern
France where all red wines are made using this process. For true carbonic macera-
tion, sound uncrushed clusters of grapes are loaded into a closed vessel (best results
are obtained if the vessel has been pre-filled with carbon dioxide gas), and then left
for 1-2 weeks during which the grapes respire any remaining oxygen and eventu-
ally 'drown' in carbon dioxide. The colour then permeates from the skin cells into
the grape flesh, and there is also some alcohol production, loss of acidity and fla-
vour production characteristic of the technique. The grapes are then removed from
the tank and pressed, and the resulting red, partly-fermented juice is treated as any
other juice/wine after pressing.
Heat Extraction
The pigmented skin cells of red grapes release their colour into the juice of the grape
when heated. A number of methods are used industrially to heat freshly-crushed red
must and then to drain and cool the coloured juice which is then treated as a white
juice.
Pressing of Whites and Reds
In red winemaking, colour extraction is largely complete after 3-4 days of fermen-
tation. After this period, extraction of phenolic material (which provide astringency
and bitterness) is the most important reason to continue post ferment maceration.
The winemaker must decide on the desirable amount of phenolic extraction and
then the ferment is drained off as the 'free run' component. The remaining wet skins
and seeds are transferred to the press, generally manually or directly into the press
by gravity.
Basket presses. These are the oldest and simplest form of press still used, and
consist of a basket of wooden slats seated in a steel juice-collecting tray. The wet
marc is loaded into the basket and then compressed by a large plate which is forced
hydraulically or by screw into the basket.
