Processing
Cherries fermented in sealed tanks without oxygen. Produces intense, unusual and divisive flavours that can overwhelm the origin.
Anaerobic fermentation seals coffee cherries — whole, depulped, or in various combinations — in airtight tanks so that fermentation happens without oxygen.
It is the most talked-about development in coffee processing of the last decade, and the most divisive.
Fermentation is microbial, and which microbes dominate depends on the environment. Excluding oxygen favours a different population than open-air fermentation, and those microbes produce a different set of compounds.
Producers control temperature, duration, pH and sometimes add specific yeast cultures. It is closer to winemaking than to traditional coffee processing.
Intense and unusual. Common descriptors include cinnamon, tropical fruit, whisky, rum, bubblegum, and — at the extreme — something close to solvent.
The critical point is that these flavours come from the fermentation, not from the bean or the place. A well-made anaerobic lot can be spectacular. It also tends to taste like an anaerobic lot rather than like Colombia or Ethiopia, which is exactly what some drinkers object to.
Two objections are worth taking seriously.
It can mask origin. If the process dominates, the terroir that specialty coffee exists to celebrate becomes irrelevant.
It can mask poor coffee. A strong fermentation profile hides defects that a washed process would expose, and mediocre beans can be sold at high prices on process alone.
Carbonic maceration borrows the winemaking technique of fermenting whole fruit under CO₂. Thermal shock adds hot and cold water cycles. Co-fermentation adds fruit, spices or cultures — the most contested of all.
Use a clean, revealing method — a V60 or a Kalita — and brew lighter than you would a natural. These coffees are usually roasted very light and have plenty to give.
Excluding oxygen changes which microbes dominate the fermentation, and different microbes produce different compounds. The results — cinnamon, tropical fruit, whisky, bubblegum — come from the fermentation rather than from the bean or the place.
Partly, and not entirely. Done carefully it produces genuinely novel and delicious cups. Done carelessly it produces coffee that tastes of fermentation and nothing else, and it is charged for at the same price.
The equipment this actually requires — not a shopping list, the shortest route to doing it properly.
60° cone · spiral ribs · 1–4 cups
The most transparent cup you can brew for twenty euros, and the least forgiving. Ceramic holds heat where plastic does not — and the open bottom means your pour, not the dripper, decides the coffee.
Best for: Someone who wants to taste what a single-origin coffee is actually doing.
≈ $25 / £20 / 22 €
64 mm flat burr · filter only · single dose
64 mm flat burrs, near-zero retention and a footprint the size of a mug, built for filter and honest about not doing espresso. For pour-over it is the clearest grind you can buy at this price.
Best for: V60, Chemex, AeroPress and batch brewing, where clarity is the whole point.
≈ $345 / £275 / 300 €
