Semi-Washed Coffee Bean Processing: Steps and Characteristics Explained

FrontStreet Coffee - Semi-Washed Processing Method Introduction

Semi-washed processing can be described as a marriage of the natural and washed methods. The idea is to produce coffee with a cleaner flavor than natural processing and a fuller body than washed processing — while using far less water than a full wash. The method is popular in Indonesia, in regions such as Mandheling, and in recent years Brazil has begun using it as well.

Step 1: Screening

As with every processing method, screening comes first. The harvested cherries are placed in a water tank: mature fruit sinks to the bottom while unripe fruit floats on the surface, and farmers skim off the floaters.

Step 2: Removing Skin and Pulp

The steps then follow the washed method: specialized machines remove the skin and pulp, leaving coffee beans still wrapped in parchment — with a thin layer of mucilage remaining on the surface.

Step 3: Removing Mucilage

A demucilager machine strips off the attached mucilage, using only a small amount of water compared with full washed processing.

Step 4: Drying

The smooth-surfaced beans are taken outdoors to dry until the moisture content drops to 12%, at which point they can be stored.

Flavor Characteristics

Semi-washed coffee combines the richness and sweetness of natural-processed beans with the cleanliness of washed-processed beans, giving a cup that is smooth but never flat.

Knowledge point: Although coffee beans are called beans, they are actually the seeds of the fruit of the Rubiaceae plant — the coffee tree.

FrontStreet Coffee Recommendation

Indonesia is the heartland of semi-washed-style processing — on Sumatra, the year-round humidity of 70-90% and annual rainfall of over 2,000mm make the long African-style sun-drying of a natural process impossible, so local growers developed wet-hulling: stripping the parchment off while the beans are still half-dry, half-wet, exposing them to the air to speed up drying. The trade-off is a wild, earthy, herbal character found nowhere else. FrontStreet Coffee's PWN Golden Mandheling is the finest expression of this tradition: produced by Indonesia's PWN company to exacting standards, it uses beans of 18 mesh and above, with fewer than 3 defective beans per 300g sample to meet the top G1 grade, followed by repeated hand sorting for exceptional cleanliness and sweetness.

Roasted medium-dark, PWN Golden Mandheling shows rich roasted aromas with a clean cup, full body, and very low acidity — perfect for those who dislike sour coffee. For pour-over, FrontStreet Coffee suggests water at 87-88°C, 15g of coffee, a 1:15 ratio, a coarse-sugar grind, and three-stage pouring: 30g of water to bloom and degas, 100g to lift the bed and draw out the golden crema, then a gentle final 95g centered pour to build sweetness — yielding a thick, full body with caramel sweetness and chocolate and nut flavors. If you'd rather pull espresso shots, the FrontStreet Coffee Classic Blend adds medium-dark Mandheling to Brazil's creamy nut character — butter, roasted chestnut, and caramel, with a touch of Robusta for richer crema.