Washed Process

The washed process — also called wet process — is the most widely used method in specialty coffee and the de facto benchmark against which other processes are measured. Its purpose is simple: remove all of the coffee cherry before the bean is dried, so that what ends up in your cup is an expression of the bean itself, not the fruit around it.

The Process Step by Step

1. Harvesting: Ripe cherries are selectively hand-picked (in most specialty contexts) and delivered to the washing station or wet mill.

2. Depulping: A mechanical depulper removes the outer skin and most of the pulp from the cherry, leaving the bean surrounded by a sticky mucilage layer.

3. Fermentation: The depulped beans — still coated in mucilage — are placed in fermentation tanks filled with water (or dry, in dry-fermentation variants). Naturally occurring microorganisms (bacteria and yeasts) break down the remaining mucilage over 12–72 hours depending on altitude, temperature, and the producer's target profile. The fermentation window must be carefully managed: too short and mucilage remains, too long and defect flavours (overripe, vinegar, putrid) develop.

4. Washing: After fermentation, the beans are flushed through washing channels with clean water, which removes the dissolved mucilage and halts fermentation. The clarity and volume of wash water used affects the cleanliness of the final cup — this is where Kenyan double fermentation (a second soaking in clean water after the first wash) occurs.

5. Drying: Clean, washed beans are dried on raised drying beds or patio surfaces, typically for 1–3 weeks, to reach a stable 10–12% moisture content. Raised African beds allow airflow from below and above, promoting even drying. Drying on concrete patios is faster but less even.

What Washed Process Does to the Cup

Removing the fruit eliminates most of the sugars that would otherwise migrate into the bean during natural drying. The result is a cup with:

• Higher perceived acidity: Without fruit sugars masking it, the organic acids in the bean (malic, citric, tartaric) read cleanly and brightly.
• Clarity: Less suspended matter, cleaner finish, more defined individual flavour notes.
• Terroir transparency: The origin's character — its altitude, soil, variety, microclimate — has less interference from fermentation. A washed Yirgacheffe tastes of Yirgacheffe; a natural Yirgacheffe tastes of Yirgacheffe filtered through heavy fruit fermentation.
• Lighter body: No fruit residue, fewer dissolved solids, less mouthfeel compared to natural or honey process.

Why It's the Benchmark for Origin Character

When Q-graders and buyers want to assess an origin or variety's intrinsic quality, they typically request washed samples. The washed process introduces the fewest variables between the growing environment and the cup. If the terroir is interesting, the washed process shows it. If the variety is distinctive, the washed process reveals it. It is the least adulterated expression of what the coffee is.

This is why washed processing dominates Ethiopia's high-end export market, why Kenyan specialty is almost exclusively washed, and why Colombian specialty coffee is predominantly washed. The goal in these origins is to showcase terroir, and the washed process is the most direct route to that goal.

Ideal Roasting and Brewing

Washed coffees reward light-to-medium roasting, where the origin acidity, florals, and fruit notes can express fully. Taking a washed Ethiopian to a dark roast burns off most of what makes it interesting — the terroir character is replaced by roast character.

In the cup, washed coffees are best brewed at slightly higher water temperatures (93–96°C) compared to naturals, because they often need more energy to fully extract their denser, less-porous bean structure (particularly at high altitude where beans are denser). The V60 and Chemex are natural homes for washed coffees — their paper filters and clean extraction match the process's clarity-forward character.