Processing: washed, natural, honey, anaerobic

A coffee cherry is a fruit with a seed inside it. Processing is the business of removing the fruit — skin, pulp and the sticky mucilage layer — and drying the seed to a stable moisture content of around 10 to 11 per cent. How much fruit contact the seed gets, and for how long, and under what conditions, determines much of the final flavour.

Washed

The cherry is pulped, the remaining mucilage is removed by fermentation and washing, and the clean parchment is dried. Washed processing removes the fruit's own flavours from the equation and leaves the variety and the terroir exposed with nothing to hide behind.

For Geisha this is the classical choice and the one most competition winners use. It gives the purest jasmine and bergamot, the brightest citric acidity, the most tea-like body and the cleanest finish. It is also the most unforgiving: any weakness in the farming shows immediately. If you want to understand what Geisha is, start here.

Natural (dry process)

The whole cherry is dried intact on raised beds or patios, often for two to four weeks, and only then hulled. The seed sits inside its own fermenting fruit throughout.

Natural Geisha trades some clarity for a great deal of fruit: strawberry, blueberry, mango, papaya, tropical intensity, a heavier and sweeter body. Done well it is spectacular. Done badly it is a mess of over-fermented, boozy, vinegary flavours. Natural processing has become the higher-risk, higher-reward option, and the top natural lots now regularly out-sell washed lots at auction.

Honey

A middle route: the skin is removed but some or all of the mucilage stays on the bean during drying. The amount left behind gives the names — white, yellow, red and black honey, in ascending order of mucilage and body. Honey-processed Geisha keeps the floral aromatics of a washed coffee but gains sweetness and a rounder texture. It is a good choice for espresso and for anyone who finds strictly washed lots too austere.

Anaerobic and carbonic maceration

The modern additions. Cherries or pulped beans are sealed in stainless tanks without oxygen, sometimes under CO₂ pressure, sometimes at controlled low temperature, for anything from 24 to 120 hours before drying. Producers control temperature, pH and duration to steer the fermentation.

The results are polarising: intense, sometimes almost liqueur-like, with notes of cinnamon, rum, tropical fruit, jasmine turned up to an unnatural volume. Some buyers find they overwhelm the variety. Others build their whole offer on them. There is no correct answer, but be aware that a heavily fermented lot tastes of the fermentation first and of the Geisha second — which is an odd thing to pay a Geisha premium for.