Coffee processing is what happens to the coffee fruit after picking. Along with the variety and where the coffee grew, it's the biggest influence on how a coffee tastes: the same cherries from the same trees, picked on the same day and split into two batches, can arrive tasting like two very different coffees. Here is every coffee processing method you're likely to see on a bag, and what each one actually does.
How is coffee processed, and why?
A coffee cherry is a small sweet fruit with two seeds inside it. To sell the seeds, a producer has to get the fruit/pulp off and the seed dry, every step handled with great care so that nothing spoils. Every method below is a different answer to that, and each one leaves the fruit in contact with the seed for a different length of time. That contact time is the dial: less contact, cleaner and brighter; more contact, sweeter, fruitier and heavier.
The three classic coffee processing methods
Washed
The skin and pulp are removed normally within a few hours of picking up to a day. The seeds are left to ferment in tanks, sometimes covered with water, until the sticky mucilage breaks down, and everything is rinsed away before drying. Nothing of the fruit pulp remains on the seed.
Tastes like: clean, bright, precise. Florals, citrus, black tea, stone fruit, with lively acidity and a clean finish. It's the most transparent method — you taste the variety and the soil rather than the processing.
Common in: Kenya, Ethiopia, Rwanda and throughout most of the countries in central and south America.
Natural (dry process)
The whole coffee fruit/cherry is dried intact, fruit and all, for two to five weeks. As it dries, sugars and aromatics from the pulp move into the seed.
Tastes like: sweet, round, heavy. Strawberry, blueberry, tropical fruit, sometimes a winey note. Softer acidity, fuller body.
Common in: Ethiopia, Brazil, and increasingly everywhere.
These two are the poles that everything else sits between, and they're worth understanding properly: washed vs natural coffee, explained →
Honey (pulped natural)
The skin comes off, but some or all of the sticky mucilage is left on the seed while it dries. How much is left, and how slowly it dries, gives the colour names — white, yellow, red and black honey, running from almost-washed to almost-natural.
Tastes like: sweetness above all. Nougat, stone fruit, apple, caramel at the lighter end; ripe fruit and berries at the darker end.
Common in: Costa Rica, where the style was refined and named, and across Central America.
The full breakdown, including what each colour means: what is honey processed coffee? →
The newer methods
Anaerobic coffee (anaerobic fermentation)
Before drying, the cherries or the pulped seeds are sealed in tanks without oxygen. The fermentation goes in a different direction than it would in open air, and the producer can control temperature and time more precisely. It's a step that can be added in front of any of the three methods above, which is why you'll see "anaerobic natural" and "anaerobic washed" on bags.
Tastes like: intense, layered, sometimes startling. Pungent, tropical fruit, occasionally something boozy like rum or amaretto.
These coffees can be spectacular, and they can also taste more of the tank than of the farm. We buy them rarely, and only when the fruit still tastes like the place it came from.
Carbonic maceration
A variation borrowed from winemaking: the sealed tank is flushed with carbon dioxide before fermentation. Same idea, more control, usually even more intense results.
Cherry rested
Picked cherries are held whole and many times cool for a period before processing begins, rather than going straight into the tank. The resting matures and softens the coffee cherries so the skins are more easily removed. The resting helps build sweetness and aroma before the process properly starts. Several of the Costa Rican and Colombian lots we buy are made this way, and it's one of the more interesting things happening at the mills we work with: what is cherry rested coffee? →
Wet-hulled
Mostly Indonesian, and included because you'll meet it. The parchment is removed while the coffee is still damp, which gives the earthy, herbal, low-acid profile you'll know from Sumatra. It's a genuine regional tradition rather than an experiment.
Does the method make a coffee better?
No — a great washed coffee and a great natural are both great. What ruins a coffee is bad execution, not the method: fruit left to rot on a drying bed is one of the worst things you can put in a cup, whatever it says on the label. What we look for, whichever route a producer takes, is that the coffee still tastes of somewhere — that farm, that terroir, that variety.
How to read the bag
Every Koppi bag carries the same five things, and read together they tell you most of what to expect before you open it:
- The producer — the name of the person or the washing station.
- The origin — micro-region, region and country.
- The cultivar — which kind of coffee tree. What that means →
- The process — this article.
- Three flavour notes — what we taste on the cupping table.
Put them together and you can make a fair guess at the cup. A washed SL28 from Kirinyaga is going to be bright and blackcurranty. A natural from Gedeb is going to be sweet and tropical. Everything beyond that is on the information card, so the bag itself stays readable.
Common questions
What is the best coffee processing method?
There isn't one. Washed shows you the variety most clearly, natural gives you the most fruit, honey gives you the a lot of sweetness with the clarity and vibrancy still intact when done well. The best method is the one done well on the farm in front of you.
What does "washed" mean on a bag of coffee?
That the fruit was removed and the seed was fermented and washed clean before drying. Expect a clean, bright cup that tastes of the variety and the place rather than the process.
What is natural process coffee?
Coffee dried inside the whole cherry, fruit and all. Expect sweetness, body and berry or tropical fruit — and a bigger difference from washed than most people expect the first time.
Where to start
The process is listed on every product page. Pick one washed and one natural from our filter coffees → and drink them on the same morning — it's the fastest way to teach your palate what processing does.
