What is the difference between raised beds and patio drying?

Raised beds (African beds) are elevated drying structures 80–120 cm off the ground, made of mesh or netting, that allow air circulation under and around cherries or parchment. Patio drying uses flat concrete or brick surfaces at ground level. Raised beds promote slower, more even drying, better hygiene (no ground contact), and generally produce cleaner, more complex cups — which is why they have become the standard in specialty coffee production.

Drying is one of the most critical post-harvest steps for final coffee quality, often underestimated compared to variety or terroir. The drying method and duration directly influence the residual moisture content of the bean (target: 10–12 %), but also the migration of sugars and organic acids from the mucilage into the bean during the wet drying phase.

**Raised beds**: invented in East Africa and popularised in the 1990s–2000s by Ethiopian and Rwandan producers, raised beds are lightweight wood or metal structures 80–120 cm above the ground, covered with fine-mesh netting. Cherries or parchment are spread in a thin layer (3–5 cm) and turned 4 to 8 times daily. The primary advantage is air circulation under and around the cherries: drying is more even, moisture evaporates from both faces, and the risk of mould development (Aspergillus, Botrytis) on the contact face is eliminated. Drying duration is typically 20–35 days depending on ambient humidity and layer thickness.

**Patio drying**: drying on patios (concrete, brick, tiles, plastic tarps) is the traditional method in many producing regions — Brazil, South-East Asia, Central America. Cherries are spread in a 5–15 cm layer on flat ground-level surfaces and raked regularly. The main drawbacks are direct ground contact (risk of microbial contamination, dust, insects), poorer air circulation beneath the cherries, and less even drying that can create persistent moisture zones favouring defect development.

**Hybrids and variants**: intermediate solutions exist — screen tables (grid tables), drying tunnels (accelerated UV-protected drying), and parabolic dryers (greenhouse-effect dryers used at high altitude). The specialty movement clearly favours raised beds for premium lots, but acknowledges that well-managed patio drying can produce excellent results in well-organised large plantation contexts.

Raised beds vs patio drying — comparison