Carbonic Maceration Coffee Processing

Carbonic maceration borrows its name and its mechanism from winemaking: Union Hand-Roasted’s explainer describes producers loading whole, unbroken coffee cherries, skins intact, into a sealed tank, then pumping it full of carbon dioxide. Because the fruit’s skin never breaks, fermentation starts inside each cherry rather than on its surface, a different chemistry than washed or standard anaerobic processing, where pulping exposes the sugary flesh to microbes from the outside in. Producers hold the tank at a controlled, deliberately low temperature to keep the ferment from tipping into heavy alcohol production, according to MTPak’s account of the coffee-industry technique.

Coffee only adopted the technique in 2015, when Australian barista Sasa Sestic built his winning World Barista Championship routine around it, adapting a fermentation method that wine writer Jancis Robinson has described as most associated with France’s Beaujolais region, as Sprudge reported at the time. Sestic’s beverage blended a 50% natural process, 50% washed carbonic maceration Sudan Rume, developed with Colombian farmer Camilo Merizalde, who grows Sudan Rume with fellow producer Julian Holguin at their farm, Finca Las Nubes, according to Sprudge. That win is generally credited with pulling carbonic maceration off the experimental fringe and onto specialty shelves, where it now sits as its own named processing category rather than a novelty, per Coffee Review’s own 2025 list.

The two Coffee Review lots behind this page’s flavor profile show what the sealed, whole-cherry ferment does to the cup: Red Rooster’s Rwanda Kungahara Carbonic Maceration reads Bing cherry, lemongrass, pomelo, agave syrup, and frankincense, scoring 95, while PT’s Villa Loyola Carbonic Maceration, grown in Pasto, Narino, Colombia, reads date, baking chocolate, lemon verbena, narcissus, and fresh-cut fir, scoring 93. Both lean toward high-toned fruit and floral intensity layered over real sweetness and body, the same register that made the process a competition talking point in the first place.

Because the whole cherry ferments rather than just the mucilage, carbonic maceration tends to push sweetness and fruit character further than a standard washed or even anaerobic-washed process, while staying cleaner than a fully natural-dried lot. That intensity is also why it rewards a gentler brew: over-extracting a bean this loaded with fermentation-driven sugars and acids is what turns a vivid cup into a boozy or medicinal one.