New Delhi, June 27 -- In Coorg's Mooleh Manay estate there's a tree species that has been around for as long as anyone can remember. They call it Excelsa. For decades, it served as a boundary tree, shielding coffee plants from fertiliser drift from neighbouring estates. It produced a small volume of beans, which the family processed for their own use. It remained a border plant, and not much else. The same was true of several estates across the region.

Coffee, for the most part, has meant just two species: Arabica and Robusta. And yet, there are over 133 species in the world. Coffea arabica accounts for about 55-60% of global production, followed by Coffea canephora (Robusta) at roughly 40-45%. Less than 1% comes from Liberica, Excelsa a...