What Is Washed Processing?

In washed processing, the fruit pulp is removed immediately after harvest, the bean is fermented in water for 12–48 hours, washed, and dried. The result: a clean, clear cup profile.

Why that matters

Washed processing (also called wet processing) is the most elaborate and water-intensive of the three classic processing methods. It also delivers the “cleanest” flavour profiles — the bean’s own aromas come through unmasked, without influence from the fruit pulp.

The process in four steps: First, within hours of harvest, a depulper (a mechanical pulping machine) strips the fruit flesh from the cherry. Second, the beans — still coated in a sticky mucilage layer — go into fermentation tanks, where microorganisms break down the mucilage over 12–48 hours. Third, the beans are washed with clean water to remove all residue. Fourth, they dry on raised beds (African beds) or patios in the sun until they reach a moisture content of 10–12 %.

Fermentation is the critical step. Too short, and the mucilage remains, which can make the coffee slimy and astringent. Too long, and unpleasant vinegary off-flavours develop. Experienced processors monitor temperature, pH, and duration meticulously.

In the cup, washed processing produces coffees with pronounced acidity, floral notes, and a clear, transparent body. The coffee tastes “like itself” — variety and terroir come through unfiltered. Typical examples: Colombian Huila (caramel, citrus), Kenyan AA (blackcurrant, tomato), washed Ethiopian Yirgacheffe (jasmine, bergamot).

At Green Wall Coffee

At our café on Sophienstraße 27 in Berlin-Lichtenberg, most of our filter coffees are washed — because the clear aroma profiles shine best in a pour-over. When guests ask what “washed” on the bag means, I explain the difference using two coffees side by side: a washed Ethiopian (floral, clear) next to a natural Ethiopian (berry-like, sweet). Same origin, different process — completely different flavour.

More depth on this topic in the article How to Make Perfect Espresso. Or stop by at Sophienstraße 27 — Mon–Fri 8am–5pm, Sat 10am–5pm.