Carbonic Maceration

What is Carbonic Maceration?

Carbonic maceration (French: Macération Carbonique) is a specialised vinification method in which whole, intact grape bunches are fermented in a sealed tank under a CO₂ atmosphere. This process differs fundamentally from conventional winemaking and results in characteristically fruity, fresh red wines with low tannins and intense fruit aromas.

How Does Carbonic Maceration Work?

The Process in Detail

1. Filling the tank: Whole, uncrushed grape bunches are loaded into a sealed tank
2. CO₂ atmosphere: The tank is flooded with carbon dioxide, displacing oxygen
3. Intracellular fermentation: An anaerobic fermentation begins inside the intact berries
4. Enzymatic processes: The grapes' own enzymes convert sugar into alcohol (without yeast involvement)
5. Bursting berries: After several days, the berries burst due to the build-up of alcohol and CO₂ pressure
6. Conventional fermentation: The released juice then finishes fermentation in the usual way with yeasts

The entire process typically takes 5–14 days, with the intracellular fermentation producing around 1–2% alcohol.

Characteristic Aromas

Carbonic maceration produces a very specific aroma profile:

• Banana: The most typical aroma, caused by isoamyl acetate
• Cherry drop: Artificial-seeming fruity cherry notes
• Bubblegum: Sweet, synthetic fruit aromas
• Strawberry: Fresh, intense strawberry notes
• Flowers: Violet and other floral accents

These aromas arise from the anaerobic conditions and differ markedly from traditionally fermented wines.

Advantages of the Method

• Intense fruit aromas: Maximum emphasis on fresh primary fruits
• Low tannins: Gentle extraction through careful treatment of the grape skins
• Vivid colour: Bright, brilliant red wine colours
• Early drinkability: Wines are immediately enjoyable, without ageing
• Low acidity: Malic acid is partially broken down

Disadvantages and Limitations

• Limited complexity: Less structure and depth than traditional wines
• Short ageing potential: Usually intended for immediate consumption
• Artificial aromas: Banana and candy notes are not to everyone's taste
• Terroir expression: The method masks terroir characteristics

Beaujolais Nouveau – The Classic

The best-known example of carbonic maceration is Beaujolais Nouveau. This fresh Gamay red wine from Beaujolais is released each year on the third Thursday of November, just a few weeks after the harvest. Carbonic maceration enables this extremely rapid production and gives the wine its characteristic banana and candy aromas.

Semi-Carbonic Maceration

Many producers use a modified version:

• Semi-Carbonic Maceration: A portion of the grapes is crushed, the rest remains whole
• Mixed fermentation: Combination of intracellular and conventional yeast fermentation
• More complexity: A more balanced aroma profile with greater structure

High-quality Cru Beaujolais often use this hybrid method to achieve greater depth and ageing potential while retaining typical Gamay fruitiness.

Further Applications

Carbonic maceration is not only used in Beaujolais:

• Rioja: Some traditional Rioja wines use the method for Tempranillo
• Southern France: For fruity Carignan and Grenache wines
• Natural wine: Popular among natural winemakers for unfiltered, unsulphured wines
• Experimental wines: Modern producers are experimenting with the method for various grape varieties

Related Terms

• Maceration: The general process of juice extraction
• Secondary aromas: Aromas that arise through winemaking methods
• Tannins: Only minimally extracted in carbonic maceration