Josh explained that ‘carbonic’ refers to the use of carbon dioxide gas and ‘maceration’ is the winemakers term for keeping grape skins and juice together in order to colour the grapes’ clear juice by extracting pigments from their skins.
In the Carbonic Maceration process whole uncrushed grape bunches are put into a closed tank which is then filled with carbon dioxide gas in order to keep oxygen out. In this anaerobic atmosphere natural fermentation starts to take place inside individual berries.
“It is an intracellular process in which the grapes’ normal process of creating sugar is reversed and it starts eating itself: the sugar within the grape is broken down to make alcohol,” explained Josh Rude. “Although some grapes are crushed by the weight of those above, most fermentation takes place in the berry, inside its skin”.
The alcohol produced during Carbonic Maceration is too low for wine, at around 3-4% abv. So the tank is emptied, the grapes pressed and the juice is fermented in the normal manner, by the addition of yeast.
Carbonic Maceration offers a fresh fruity wine with low acids and tannins, ready for drinking young.
It is the method used to make Beaujolais Nouveau, the new wine that goes on sale each year on the third Thursday of November, within weeks of the grapes being harvested.
In Beaujolais the only grapes used are Gamay, a variety that is not widely grown elsewhere. But nouveau wines are made elsewhere from various different varieties.
Such wines, with young fresh fruity flavours, lacking tannin and acidity and best served slightly cooled, are often the first red wine enjoyed by white wine drinkers.
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Peter F May is the author of Marilyn Merlot and the Naked Grape: Odd Wines from Around the World which features more than 100 wine labels and the stories behind them, and PINOTAGE: Behind the Legends of South Africa’s Own Wine which tells the story behind the Pinotage wine and grape, also available for the Kindle.
Disclosure: Josh Rude was speaking at the American Wine Society Annual Confernce in Portland Oregon. The author travelled to the Conference at his own expense, and as a conference speaker had free entry to this seminar.