Arabica, Robusta, and the lesser-known species

Almost every cup traces back to one of four cultivated species. Arabica (Coffea arabica) makes up roughly 60–70% of world production, grows best at higher altitude (600–2,200 m), and is prized for a wider aromatic range, brighter acidity, and lower caffeine (around 1.2–1.5%) — but it's more fragile and costlier to farm. Robusta (Coffea canephora) covers most of the rest: it thrives at lower altitude, resists pests and disease far better, carries roughly double the caffeine (around 2.2–2.7%), and tends toward a bolder, more bitter, earthy or nutty cup with less acidity — traits that also give it thicker, more persistent crema, which is why some espresso blends (particularly southern-Italian style) include a portion of it.

Liberica is a small-volume species grown mainly in the Philippines and Malaysia, known for large, irregular beans and a distinctive woody, smoky, sometimes floral cup. Excelsa, now often reclassified as a Liberica variant, adds a tart, fruity note and is mostly used in small quantities within blends for complexity.