Which has more caffeine: Arabica or Robusta?

Robusta (Coffea canephora) carries roughly twice as much caffeine as Arabica (Coffea arabica): about 2.2-2.7 % of the green bean's weight, versus 1.2-1.5 % for Arabica. Brew for brew and dose for dose, a pure-Robusta espresso therefore packs 70-100 % more caffeine than a pure-Arabica shot — a meaningful gap if you monitor intake.

For the coffee plant, caffeine is a natural pesticide: it paralyses leaf-eating insects and inhibits the germination of neighbouring seedlings (allelopathy). Coffea canephora, which grows in hot humid lowlands where pest pressure is highest, evolved to produce far more of it. Coffea arabica, which lives at altitude (800-2,200 m) where cooler nights already deter many parasites, faces less evolutionary pressure and synthesises roughly half as much. Analyses in Journal of Agricultural and Food Chemistry and USDA data agree: 1.2-1.5 % for Arabica, 2.2-2.7 % for Robusta on a green-bean dry-weight basis.

In the cup the difference widens or narrows with method. For a classic 7 g Italian espresso, pure Arabica vs pure Robusta moves you from about 85 mg to about 150 mg of caffeine. A traditional Italian 80/20 Arabica/Robusta blend clocks around 100 mg — roughly 15 % more than pure Arabica. Historic Neapolitan espresso, often 40 % Robusta, lands near 115-120 mg, one reason it feels 'stronger' than a Scandinavian shot. In a 200 ml filter cup or a French press, the hierarchy stays but volume amplifies it: a Robusta filter can push past 200 mg per cup.

Beyond caffeine, the two species diverge on almost everything. Arabica is allotetraploid (44 chromosomes), high-altitude, vulnerable to coffee leaf rust (Hemileia vastatrix), pricier, and the source of the complex fruit-and-flower cups. Robusta is diploid (22 chromosomes), hardy, richer in chlorogenic acids (hence more bitter), carries more caffeine, and dominates instant, pods and industrial espresso. The Fine Robusta initiative, backed by the Coffee Quality Institute, aims to push selected Robustas above 80 points on the R-Grader protocol, but it remains niche.

In Belgium, traditional filter blends and many Nespresso-compatible capsules routinely include 10-40 % Robusta — part of why a supermarket filter can feel 'stronger' than a lightly roasted specialty Arabica despite its darker colour. Specialty roasters in Brussels, Ghent and Antwerp, by contrast, work almost exclusively with Arabica (99 % of the specialty market according to the SCA). For anyone tracking caffeine, choosing a declared single-origin Arabica is the simplest way to keep the dose in check without leaving the cup behind.

Arabica vs Robusta: caffeine and key traits