Others: Processing — A–Z

Processing (18)

• African drying beds — Waist-high mesh tables that hold drying coffee off the ground so air can move underneath it. The cheapest piece of equipment in specialty coffee and one of the few that reliably shows up in the cup.
• Anaerobic fermentation — Fermenting coffee inside a sealed container so almost no air gets in. It is not a fourth processing method — it is a knob producers turn on top of washed, honey or natural, and it is where most of the loud experimental coffee of the last decade comes from.
• Caffeine — The bitter alkaloid the coffee plant makes to poison insects — how much of it is in a bean, how much reaches a cup, what it does to a taster, and why almost every number attached to it is a range rather than a figure.
• Carbonic maceration — A wine technique borrowed by coffee — whole, un-pulped cherries sealed in a carbon-dioxide-filled tank so each fruit ferments from the inside out, still in its skin. It is the strictest cousin of anaerobic fermentation, and the two words are used loosely enough that a bag may mean either.
• Coffee fermentation — The stage after picking where microbes eat the sugary fruit layer around the coffee seed. Every coffee ferments whether the producer plans it or not — the whole art is deciding how much air the microbes get, how warm they run, and how long they work. Aerobic, anaerobic and carbonic maceration are three settings on that one dial.
• Decaffeination — How caffeine is taken out of green coffee before it is ever roasted — the water-only Swiss Water route, the ethyl acetate (EA) solvent route, and the supercritical CO₂ route — and what each one costs the cup.
• Dry milling — The last thing that happens to coffee before it leaves the country — a shed full of machines cracks the dried shell off the seed, then sizes, weighs, photographs and hand-picks the beans until what is left is clean enough to sell. Every processing method, from natural to washed, ends here.
• Honey process — The middle road between washed and natural coffee — the fruit skin comes off, but the sticky layer underneath stays on the seed while it dries. No honey involved.
• Monsooned Malabar — The Indian process that leaves already-dried green coffee out in the monsoon for three to four months on purpose — swelling the beans, bleaching them pale gold and stripping out nearly all the acidity. It is a legally protected regional product, not a variety, and it began as an attempt to recreate what a slow sea voyage used to do by accident.
• Mucilage — The sticky, sugary gel glued to the coffee seed once the fruit skin comes off. It is roughly nine-tenths water, its dry matter is mostly sugar, and the decision of what to do with it is what separates washed, honey and natural coffee. Everywhere it is washed away it becomes a pollution problem.
• Natural process — The oldest way of making coffee — the whole cherry is dried in the sun with the fruit still on the seed, then cracked open weeks later. It gives the heaviest fruit flavour of any method, and it is the hardest one to not ruin.
• Pu’er tea — The Chinese tea that is deliberately fermented by microbes after picking and then aged for years like wine — legally tied to four areas of Yunnan, sold in pressed cakes, and the closest thing the drinks world has to a working answer to the question specialty coffee keeps asking about fermentation, aging and vintage.
• Pulped natural — Brazil’s own way of preparing coffee — the cherry skin is peeled off by machine and the seed goes straight out to dry with its sticky fruit layer still on. It was invented to dry coffee faster and lose less of it, not to chase flavour.
• Selective picking — Sending pickers back through the same trees again and again to take only the ripe cherries — the single most expensive quality decision on a coffee farm, and the one that only pays if somebody downstream is buying on taste.
• Thermal shock processing — A Colombian post-harvest technique where coffee is washed in hot water and then immediately in cold water at the end of fermentation. Producers call it “bean sealing” — the idea is to stop the ferment dead and trap the aromas it made. It is a finishing step bolted onto anaerobic fermentation, not a processing method of its own.
• Washed process — The method that strips every scrap of fruit off the coffee seed before it is dried, so what you taste is the seed and the place rather than the fruit. It is the default for specialty coffee almost everywhere except Brazil, and it costs water.
• Washing station — The shed with a pulper, a set of tanks and a field of drying beds where hundreds of smallholders’ cherry becomes one sellable lot. In origins built on tiny farms, the station rather than the farm is the name on the bag — and the place quality is made or lost.
• Wet hulling — The Indonesian processing method — giling basah, “wet grinding” — that cracks the papery shell off the coffee seed while it is still soft and half-wet, months earlier than anywhere else. It is why Sumatran coffee tastes earthy, low-acid and heavy-bodied, and the one case where hulling is a flavour decision rather than a cleaning step.