Carbonic Maceration
Carbonic Maceration is a winemaking technique where whole grapes are fermented in a carbon dioxide environment.
Conventional wine making ferments crushed grapes, while Carbonic Maceration ferments the juice while it is still inside the grapes.
The process emphasizes the fresh, fruity flavors of the wine, and is used to produce wines with low tannins and vibrant aromas.
French Beaujolais is the most famous wine associated with Carbonic Maceration.
The Carbonic Maceration Processes
In carbonic maceration, whole, uncrushed bunches of grapes are placed in a sealed, carbon dioxide-filled fermentation tank. Instead of the typical method where yeast ferments grape juice after crushing the grapes, this method allows fermentation to begin inside the grapes.
Because the grapes are in an oxygen-deprived environment, they start to ferment internally through an enzymatic process. Inside each grape, sugars begin converting into alcohol without the involvement of yeast.
As the internal fermentation progresses, the grape skins eventually split open, releasing juice. At this point, traditional yeast fermentation takes over, converting the remaining sugars into alcohol.
Wine Style
Wines made with carbonic maceration are known for their bright, fruity aromas. They often have pronounced notes of red fruits (like raspberry, strawberry, and cherry), along with bubblegum, banana, and sometimes floral or candy-like qualities. These aromas are largely due to the unique chemical reactions happening inside the whole grape.
Since the process involves less contact with the grape skins, the resulting wines tend to have lower tannin levels. This makes them softer and more approachable, even when they are young.
Wines from carbonic maceration are usually fresh, vibrant, and meant for early consumption. They’re lighter in body compared to wines made with traditional fermentation methods.
These wines are made to be consumed young and fresh. They are typically best enjoyed within a year or two of release and do not have significant ageing potential. The fresh fruit character is most enjoyable when the wine is young, and it may lose its vibrancy if kept for too long.
The most famous example of carbonic maceration is Beaujolais Nouveau, which is released just weeks after the harvest. It is made to be drunk young, showcasing the fun, fruity style that carbonic maceration emphasizes.
Semi-Carbonic Maceration
In some regions, winemakers use a variation called semi-carbonic maceration.
This method blends the characteristics of two fermentation styles.
When grapes at the bottom of the tank are crushed by the weight of the grapes on the top, it starts a traditional yeast fermentation at the bottom while the upper grapes undergo a carbonic maceration.
Regions and Grapes
While carbonic maceration is most associated with Beaujolais and the Gamay grape, it is also used with other varieties like Tempranillo in Rioja and some lighter reds like Cinsault and Carignan in Southern France.
According to Jules Chauvet (the father of the french natural wine movement), carbonic maceration and natural wine fermentation with wild, local yeasts gives the best expression of the terroir.
Considerations
When selecting grapes for semi-carbonic maceration, there are several key considerations to keep in mind:
Ripeness
Grapes must be fully ripe. Unripe grapes, especially the stems, can introduce undesirable, funky flavors during the maceration process.Intactness
Grapes should be intact and undamaged. Any bruising or splitting can interfere with the fermentation process within the grape itself.Variety
Carbonic maceration is appropriate for Gamay and Grenache. Semi-carbonic for Pinot Noir, Syrah, Mourvedre and Carignan grapes.Yield Control
Grapes are often pruned short to control yield and ensure high-quality, concentrated berries.