Carbonic Maceration

In conventional red winemaking, grapes are crushed and the juice ferments in contact with the skins. In carbonic maceration, whole uncrushed grapes are placed in a sealed vessel filled with CO₂. Each grape undergoes intracellular fermentation — the grape cells begin fermenting from the inside out without yeast initially. This produces a small amount of alcohol (1–2%) inside the berry, extracting colour and fruit compounds while extracting very little tannin.

Once the berries eventually break down under their own weight, conventional yeast fermentation completes the alcoholic fermentation. The resulting wine is very light in body, low in tannin, high in fresh fruit aromas, and often has a characteristic note of banana (from isoamyl acetate) and bubblegum (from ethyl acetate esters).

Carbonic maceration is most famously associated with Beaujolais Nouveau — the ultra-fresh, young wine released every November from the Gamay grape. The Beaujolais Crus use a modified form (semi-carbonic maceration, where some berries at the bottom are crushed and ferment normally) which produces slightly more structured wines.

At Level 2 and above, carbonic maceration is linked directly to Beaujolais and Gamay in exam questions.