What is Carbonic Maceration?
Carbonic maceration is a type of fermentation that takes place in a sealed, oxygen-free environment filled with carbon dioxide. Whole coffee cherries are placed into airtight tanks or barrels, and CO₂ is pumped in to replace the oxygen. This creates the right conditions for a type of fermentation that happens inside the fruit itself—known as intracellular fermentation.
Originally developed for winemaking, the method became known in coffee after Sasa Sestic used it to win the World Barista Championship in 2015. Since then, it's grown in popularity among innovative producers looking to create coffees with distinctive flavour profiles.
The process starts with freshly harvested, fully ripe cherries. These are carefully sorted and placed into sealed tanks. As the cherries ferment in the CO₂-rich environment, enzymes and microbes inside the fruit begin to break down cell walls, allowing chemical reactions to take place that wouldn’t occur in standard aerobic processing. The result is a slow, controlled fermentation that can enhance certain flavour compounds.
Coffees processed this way often have intense and complex profiles—bright acidity, strong red fruit notes, florals, or even wine-like characteristics. Because the environment is so controlled, producers can fine-tune the outcome by adjusting variables like temperature, pH, and fermentation time.
Carbonic maceration isn’t easy. It requires precision, experience, and the right infrastructure. Done wrong, it can lead to over-fermentation or unpleasant flavours. It’s also expensive, which is why it’s still relatively rare. But when it’s done well, it produces expressive, standout coffees that often fetch higher prices and gain attention in competitions and specialty markets.
Carbonic maceration explained in simple terms
Carbonic maceration is a special way to ferment coffee cherries. They’re sealed in tanks filled with carbon dioxide instead of air. This helps bring out bright, fruity and floral flavours in the coffee. It’s a careful process that needs skill, but it can make some really exciting coffees.