What is Coffea arabica?

Coffea arabica is the coffee species behind most of the coffee drunk worldwide and almost all specialty coffee. Native to the highland forests of south-western Ethiopia, it is a tetraploid, self-pollinating species prized for the aromatic finesse and sweetness it delivers in the cup.

Coffea arabica is a shrub of the Rubiaceae family that can reach 8 to 10 metres in the wild but is typically pruned to 2 or 3 metres on plantations. Formally described by Linnaeus in 1753, the species is in fact far older: genomic studies place its origin between 10,000 and 20,000 years ago, from a single natural hybridisation between Coffea canephora (mother) and Coffea eugenioides (father) in what is today south-western Ethiopia. It is one of the very few cultivated plants that is both allotetraploid (2n = 44 chromosomes) and self-pollinating, which is why the arabica population grown outside Ethiopia rests on an unusually narrow genetic base.

Arabica bears fruit called cherries, turning from green to red (sometimes yellow or orange depending on the variety) in 7 to 9 months. Each cherry normally contains two seeds (two plano-convex hemispheres) and, more rarely, a single rounded bean known as a peaberry. The tree flowers after the dry season in clusters of white, strongly jasmine-scented blossoms, and typically yields 2 to 5 kg of fresh cherries per year — roughly 400 g to 1 kg of green coffee. It demands altitude (1,000-2,200 m), stable temperatures between 18 and 24 °C, regular rainfall (1,500-2,500 mm/year) and well-drained volcanic soils, which is why its cultivation is confined to the so-called Coffee Belt between the tropics of Cancer and Capricorn.

Botanically, Arabica gathers around a hundred recognised varieties — Typica, Bourbon, Caturra, Geisha, SL28, Pacamara, Ethiopian Heirloom among many others — all descended from that common genetic matrix through spontaneous mutations or human selection. The species accounts for roughly 60 % of global green coffee output (6 to 7 million tonnes per year) and for virtually every lot scoring 80+ with the Specialty Coffee Association, apart from the Fine Robusta niche. Fragility is its Achilles' heel: coffee leaf rust (Hemileia vastatrix) wiped out Ceylon's plantations in the 19th century and hit Central America hard in the 2010s. Facing climate change, World Coffee Research is developing F1 hybrids that splice arabica genetics with robusta resilience. In Belgium, the shift toward 100 % specialty Arabica took root in the 2010s in Brussels, Ghent and Antwerp, alongside a filter tradition that had long accepted a share of Robusta.

Coffea arabica in six data points