In 2015, a Serbian-Australian barista named Saša Šestić won the World Barista Championship with a coffee no one had heard of processed in a way the coffee industry hadn't seen before. The method was carbonic maceration — borrowed directly from winemaking — and the win put it on the specialty coffee map overnight. A decade later it's no longer a novelty. The Nicaragua Parainema we're running right now is processed this way, and it's worth understanding what that actually means.

Where it comes from

Carbonic maceration has been used in wine production for decades, particularly in Beaujolais, where whole grape bunches ferment in carbon dioxide-rich tanks before being crushed. The CO₂ environment triggers fermentation inside the grape itself — intracellular fermentation — producing wines with a particular softness and intensified fruit character. Šestić saw the same logic applying to coffee cherries and worked with Colombian farmer Camilo Merizalde to test it. The result was a competition-winning cup with an aromatic complexity that washed and natural processing couldn't replicate in the same way. The industry took notice.

What actually happens

Ripe cherries are selected — and this matters, because sugar content at harvest directly affects what fermentation has to work with — then loaded into sealed stainless-steel tanks. Carbon dioxide is introduced, oxygen is forced out, and the cherries begin fermenting in an oxygen-free environment. Temperature, pH, and brix levels are monitored throughout. Depending on the producer and the target profile, fermentation runs anywhere from a few days to several weeks.

The sealed environment does two specific things. First, it changes which microorganisms drive fermentation. Open-air fermentation favours yeast; the oxygen-restricted environment inside a sealed tank favours lactic acid bacteria, which produce different volatile compounds and a different acid structure in the finished cup. Second, the pressure that builds inside the tank as CO₂ accumulates pushes compounds from the fruit into the seed more aggressively than they would migrate under normal conditions, intensifying certain flavour characteristics.

After fermentation, the coffee is dried — usually on raised beds — and in many cases rested in parchment for an extended period before hulling. That rest matters. It allows the profile to stabilise rather than arriving in the roaster still volatile from processing.

What it produces

The signatures of carbonic maceration are weight, sweetness, and a particular kind of fruit intensity that sits differently to natural processing. Where a natural-processed coffee tends toward exuberant, sometimes fermented fruit — blueberry, tropical, wine — a well-executed carbonic maceration tends to produce something richer and more layered: boozy stone fruit, dark chocolate, dried fruit, warm spice. The acidity is usually lower and softer than a washed coffee. The body is heavier. The finish tends to linger.

The Nicaragua Parainema is a useful example of the method working as intended. Dark chocolate and rum-soaked raisin at the centre, warm spice underneath, orange peel lifting the finish. The fermentation built depth; the 14-week parchment rest let it settle into something composed rather than chaotic.

Not every carbonic maceration coffee lands this way. The method requires real precision — temperature management, cherry quality, timing — and when those variables are off, the result is astringency, bitterness, or a muddiness that obscures everything interesting about the origin. The equipment alone is a significant investment, which is partly why well-executed CM lots are more expensive and less common than standard processed coffees. When it's done properly, though, the result is a cup that doesn't quite resemble anything else in the range.

How to brew it

Carbonic maceration coffees extract differently to washed lots. The fermentation process changes the cellular structure of the bean and the chemical composition of the cup, which means your standard recipe is probably not the right starting point.

For filter: start coarser than your usual grind and slightly cooler — 88–90°C rather than 93–94°C. The aromatics in these coffees are more volatile than a washed coffee and high heat can flatten them. Adjust from there rather than chasing a washed coffee recipe.

For Aeropress: low temperature, short steep, and less agitation than you might use with a natural. These coffees tend to give up their flavour quickly and over-extraction turns the warmth into bitterness.

For espresso: pull long, give it a few extra days off-roast, and accept that it will behave differently to a blend. The reward is an espresso that tastes nothing like your house blend. That's the point.