WHAT IS CARBONIC MACERATION?

Carbonic maceration is a winemaking technique primarily used for early-release red wines like Beaujolais Nouveau. This process results in fruity, low-tannin, and highly aromatic wines.

THE PRINCIPLE OF CARBONIC MACERATION

To perform this winemaking method, the grapes are hand-picked. The berries must remain intact during the vatting process, as mechanical harvesters slightly crush the grapes.

Whole clusters are harvested without crushing or destemming and are placed into fermentation tanks saturated with carbon dioxide (CO2) to remove all oxygen. The tanks are then hermetically sealed. In the absence of oxygen, the natural yeast remains inactive, and traditional fermentation cannot occur. Instead, an enzymatic fermentation begins, where the natural enzymes in the grape berries convert the sugar into alcohol.

This is also called intracellular fermentation because it occurs inside the grape berry. Wide and shallow tanks are recommended to prevent the grapes from being crushed.

After some time, the grapes in the tank will burst. At this point, they are gently pressed. The partially fermented juice obtained is then placed into a second fermentation tank in the presence of oxygen so that traditional yeast fermentation can continue.

The lack of contact between the fermenting must and the grape skins limits tannin extraction. There are variations of carbonic maceration depending on the production region.

BEAUJOLAIS NOUVEAU AND SEMI-CARBONIC MACERATION

This wine, eagerly anticipated and celebrated every third Thursday of November, is made using semi-carbonic maceration. Here’s a brief overview of the phenomenon before diving into technical details.

Beaujolais Nouveau officially came into existence in 1951 after a prefectural decree stating that “producers were not allowed to release wines from the 1951 harvest benefiting from the controlled designation of origin before December 15, 1951.” The Beaujolais union sought to sell their wines before this date. Thus, the “Nouveau” label was created, which is not an appellation but a mention applied to AOC Beaujolais and AOC Beaujolais Villages wines.

The commercial success of Beaujolais Nouveau began in Paris in the 1950s when the Lyonnaise lifestyle was admired. The phenomenon continued abroad, notably in Japan, where the release of Beaujolais Nouveau is still a significant celebration today.

In Beaujolais, a variation called “semi-carbonic” maceration is used. Whole grapes are placed in a sealed tank without adding carbon dioxide. The weight of the grapes naturally crushes those at the bottom, and the present yeast starts to consume the sugar, creating alcohol and CO2. The CO2 produced at the bottom gradually fills the tank, leading to enzymatic fermentation in the upper part of the tank now deprived of oxygen.

Carbonic maceration lasts an average of four days for Beaujolais Nouveau, six to eight days for Beaujolais and Beaujolais Villages, and ten to fourteen days for the ten crus (Saint Amour, Juliénas, Chénas, Moulin à Vent, Fleurie, Chiroubles, Morgon, Régnié, Côte de Brouilly, Brouilly).

The free-run juice (naturally released by the weight of the grapes) is then drawn off, and the remaining grapes are directly pressed. Depending on the winemaker’s choices, the press juice may or may not be combined with the free-run juice for the final alcoholic fermentation. This fermentation is carried out at low temperatures (between 18°C and 20°C) to preserve the fruity aromas of the wine and its “primeur” character. For Beaujolais Nouveau, the wines are directly bottled.

Carbonic maceration produces “gouleyant” (easy-drinking) Gamay-based wines with a certain roundness and distinctive aromas. Typical notes include kirsch, banana, candy, and cinnamon.

Carbonic maceration is also used in other wine-producing countries, such as Spain with Tempranillo, and in other French regions like Gaillac, which also uses Gamay to produce its primeur wines. In Languedoc-Roussillon, winemakers primarily use carbonic maceration with Carignan to soften its notoriously hard tannins.

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