Anatomy of Extraction: How Grape Juice Becomes Red Wine

In winemaking, maceration refers to the process of steeping grape must with the solid parts of the berry—skins, seeds, and sometimes stems. The pulp of almost all wine grape varieties (with rare exceptions like Alicante Bouschet) is colorless. If you press the juice and immediately separate it from the skins, you get white wine. To obtain red wine, the must must spend time in contact with the pomace.

During this contact, two parallel processes occur: the extraction of coloring pigments (anthocyanins) and the extraction of polyphenols (tannins). Anthocyanins are responsible for the depth and hue of the color, from pale ruby to almost black. Tannins shape the wine's structure, its astringency, and its ageing potential. Maceration also infuses the must with varietal aromas, which are primarily concentrated in the outer layers of the skins.

In the Italian region of Piemonte, the traditional approach to Nebbiolo (used for Barolo and Barbaresco) involves ultra-long post-fermentation maceration, which can last 30 to 50 days. By the time it ends, fermentation is complete, and the young, high-alcohol wine remains in contact with the skins and seeds.

This method extracts the maximum amount of tannins, which are naturally very firm in Nebbiolo. The resulting wine is pale in color but incredibly complex and capable of evolving in the bottle for decades. Modern winemakers sometimes reduce this period to 7–10 days using rotary fermenters to make the wines more approachable in their youth.

Extended skin contact requires perfect grape ripeness. If harvested too early, green, bitter tannins from unripe seeds will leach into the wine, and even years of oak ageing will not soften them.

Winemakers in Bourgogne work with the finicky Pinot Noir, a variety characterized by thin skins and low pigment content. This region pioneered the trend of cold pre-fermentation maceration. The legendary winemaker Henri Jayer popularized this method in the 1970s, aiming to produce rounder, more fruit-forward wines.

The Burgundian approach is built on balance. After a cold start, fermentation is carried out at moderate temperatures to avoid over-extracting harsh tannins. Cap management (pigeage) is performed gently, often by hand, to avoid crushing the seeds.

The result is the classic Burgundian style: a translucent ruby color, a complex bouquet of red berries and forest floor, and a fine, almost weightless tannin structure.

South of Bourgogne, in the Beaujolais region, a completely different method is used: carbonic maceration. Whole, intact clusters of Gamay are placed in sealed tanks filled with carbon dioxide. Under the weight of the grapes, the bottom berries crush and begin to ferment, while intracellular fermentation starts inside the intact upper berries without yeast.

During this process, enzymes inside the berry break down malic acid and extract aromatic compounds from the skin without oxygen contact. Tannins are barely extracted because the skins remain intact.

Beaujolais Nouveau wines made with this technique feature minimal tannins, a light body, and distinctive, vibrant aromas of banana, pear drops, and ripe red berries.