One plant, two species
Arabica is the species Coffea arabica. Robusta is Coffea canephora, sold under its best-known variety name. Arabica began as a natural cross between Coffea canephora and another coffee species, Coffea eugenioides. So robusta is one of arabica's parents. The two trees also breed differently. An arabica tree can pollinate its own flowers. A robusta tree cannot, so robusta farms mix several clones.
How arabica tastes and where it grows
Arabica is usually the sweeter bean. It has more acidity than robusta. Its flavours cover a wide range: floral, fruity, chocolate, caramel. The unroasted bean usually holds more sugar and more oil than robusta's. Arabica likes high altitude and cooler weather, usually around 1,200 to 1,500 metres. It does best where the average temperature is 15 to 24 degrees Celsius. It started in Ethiopia. Brazil grows the most today.
How robusta tastes and where it grows
Robusta is the strong, full-bodied bean. It has less acidity and more bitterness than arabica. Typical notes are earth and wood. Cheaper grades add a rubbery note. Much of robusta's rough reputation comes from poor processing rather than the bean. Fine robusta is graded to the same standard as specialty arabica. The tree gives high yields on warmer, lower land, 200 to 800 metres. Vietnam grows the most today.
Caffeine, and why robusta has more
A robusta bean carries roughly 1.5 to 2 times as much caffeine as an arabica bean. Caffeine is the plant's natural insect deterrent, so the extra dose helps robusta fend off bugs. Arabica, for its part, is susceptible to leaf rust and to the coffee berry borer. Robusta is not immune to rust either, just less susceptible. The table below lines up both species, with liberica alongside.
| Arabica | Robusta | Liberica | |
|---|---|---|---|
| Species | Coffea arabica | Coffea canephora | Coffea liberica |
| Caffeine, green bean | About 0.9-1.3% | About 1.5-3.3% | No reliable figure found |
| Where it grows | High, cool land, often 1,200-1,500 m | Warmer, lower land, about 200-800 m | Philippines, Malaysia, Indonesia |
| Share of world coffee | About 56% (USDA forecast, 2026/27) | About 44% (USDA forecast, 2026/27) | Under 1.5% |
| Taste | Sweeter, more acidity; floral to chocolate | Stronger, more bitter, earthy, woody | Fruity, like jackfruit |
What 100% arabica means on the bag
100% arabica means every bean in the bag is Coffea arabica. It tells you the species and nothing more. A blend can be all arabica, or arabica with some robusta. Italian espresso blends often add quality robusta for body and more crema. Most robusta, though, goes into instant coffee.