The Sun-Drying Process of Coffee Beans - Characteristics of Sun-Dried Coffee Beans: A Fine Line Between Delicious and Not

FrontStreet Coffee - Introduction to Natural Coffee Processing

Once coffee cherries are picked from the tree, the outer skin, pulp, and mucilage have to be removed. That step is called green bean processing. For a single coffee variety there are several processing methods, and the method chosen largely determines the flavor and quality of the final coffee.

Natural Process

The natural process is the oldest and most traditional way to process coffee. Harvested cherries are first poured into large water tanks. Ripe, full fruits sink to the bottom, while underdeveloped or overripe fruits float to the surface. After the floaters are removed, healthy cherries are spread on patios to dry directly in the sun, bringing moisture down from 60% to 12%-15%. Finally, a hulling machine removes the hard, dry outer skin and pulp, completing the process and leaving the green beans.

The natural process can enhance berry and tropical fruit flavors with mild fruit acidity. Traditional natural methods, however, sometimes produce negative flavors, such as earthy or over-fermented notes.

Today the natural process is enjoying a revival and has become one of the important processing methods for competition-grade coffee. The change comes from the use of improved African raised beds. Raised beds not only keep the fruit away from ground moisture, animal waste, and earthy flavors, but also place it in good air convection so it dries more evenly. Farmers turn the cherries regularly, letting them gently absorb sweetness from the pulp so that the flavor grows richer and richer.

Knowledge Point

Depending on how much mucilage is retained, honey processing is further divided into yellow honey, black honey, and other styles.

In Brief

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FrontStreet Coffee Recommendation

Natural processing is the oldest way to process coffee and remains the most widely used method today. Sun-drying simply means spreading ripe cherries in the sun right after harvest until the moisture content is on target, then hulling them to get the beans we want. Because the fruit is kept intact during drying, naturally processed coffee has a fuller body and more easily develops a rich, ripe-fruit character. The method is demanding when it comes to weather, since it needs a stretch of clear days, and drying typically runs 27 to 30 days. Ethiopia uses natural processing widely, because its very high altitude, dry climate, and scarce water make it ideal. Locals pick ripe cherries and spread them flat on mesh racks to dry. FrontStreet's Red Cherry comes from the famous Yirgacheffe region and uses only fully ripe, all-red cherries, spread on raised drying beds to keep them off the ground and away from insects, dust, and bacteria, with regular turning to avoid uneven heating. After a medium-light roast, FrontStreet Red Cherry shows elegant florals and bright acidity alongside clear tropical fruit, a full fermented character, and sweetness.

When it comes to natural coffee, FrontStreet's Huakui is impossible to overlook. Its very high altitude, exceptional growing environment, fertile soil, and carefully selected ripe cherries give FrontStreet Huakui a delicate fragrance on their own, and the representative natural processing of Sidamo draws out its graceful aroma even more. FrontStreet Huakui is an Ethiopian bean from Africa, and African coffees often show a light, floral-fruit character with prominent acidity. To highlight those traits, FrontStreet Huakui is roasted medium-light, so the cup brings soft fermented notes, florals, citrus, and mango, with a much richer, more complex body, honeyed sweetness, cocoa tones with a little spice, a full body, and a long finish.

Among natural beans, FrontStreet's 2013 Yunnan Typica is grown and produced on FrontStreet's own estate. Yunnan does not have four distinct seasons, only a dry season and a rainy one, and the cherries happen to ripen when the weather is sunniest, so natural processing is the natural choice. After long sun exposure the beans keep their nutty character while gaining a balance of sweet and tart, with a touch more sweetness than a typical washed coffee and a higher sense of balance: berry-like acidity woven with dried apricot, brown sugar, and a light tea note. FrontStreet's Brazil Queen Estate takes a different route. Most of Brazil favors pulped-natural processing, but Queen Estate dries the cherries directly on racks, turning them constantly so every bean meets the sun, then finishes with mechanical drying to reach the right moisture. The result is a stable bean with low moisture that keeps well. Brewed as pour-over, in a French press, or as a drip bag, FrontStreet Queen Estate offers the fresh sweetness of sugarcane juice, black tea, a soft, flowing fruit sweetness, clear nutty notes, balanced and gentle acidity, a faint, clean bitterness, and rich chocolate and nut aromas, with a bright, refreshing, smooth, and delicate body. Finally, unlike a conventional natural coffee, FrontStreet's Colombia Sidra uses a double anaerobic natural process, meaning the beans undergo two rounds of anaerobic fermentation before drying. Also called carbonic maceration, this method seals freshly picked whole cherries in a tank and adds carbon dioxide to drive out oxygen, creating an oxygen-free environment that slows the breakdown of sugars in the mucilage and the drop in pH, giving the beans higher sweetness, more complex flavor, and a dense, velvety texture. The beans are then dried on beds until the moisture target is reached and hulled. The double anaerobic natural process gives FrontStreet Sidra a deep tropical fruit aroma, with a complex cup of passion fruit, apricot, dried fruit, grape, and an almond-like note.