Two species, nearly all the coffee
Nearly every cup of coffee in the world comes from one of two plants. Coffea arabica makes up about 60% of the world's coffee. Coffea canephora, sold as robusta, makes up most of the rest, about 40%.
They're different enough that you can usually taste it, and often see it in the beans.
The difference at a glance
| Arabica | Robusta | |
|---|---|---|
| Share of world coffee | About 60% | About 40% |
| Caffeine (by weight of the bean) | About 1.2 to 1.5% | About 2.2 to 2.7% |
| Grows | High and cool, about 1,000 to 2,000 m | Low and hot, from sea level to about 800 m |
| The plant | Fragile, smaller harvests | Tough, bigger harvests |
| Taste | Sweeter, softer, bright acidity | Bitter, earthy |
| The bean | Longer, S-shaped crease | Rounder, smaller, straight crease |
Both grow outside those altitude ranges too; they're the typical ones.
Why robusta has more caffeine
Caffeine is bitter, and for the plant it works as a natural insect repellent. Robusta grows low down, in hot places where pests thrive, and it carries about twice the caffeine of arabica. That fits with the name: a tough plant for tough conditions. (The link between the lowlands and the extra caffeine is the common explanation rather than settled science, but the caffeine numbers themselves are solid.)
Why arabica tastes sweeter
Arabica has roughly twice the sugar of robusta, and more oils. In the cup that shows up as sweetness, brightness and a softer feel. Robusta, with more caffeine and less sugar, tastes more bitter and earthy.
How to tell the beans apart
Tip a few roasted beans into your hand and look at the line down the flat side:
- Arabica: a longer oval with an S-shaped crease.
- Robusta: smaller and rounder, with a straight crease.
In a cheap blend you'll often find both in the same scoop.
Where robusta turns up
Robusta isn't just the cheap option. You'll find it in:
- Instant coffee, which is often robusta.
- Cheaper blends.
- Many Italian espresso blends, on purpose. A share of robusta gives a thicker crema, more body and more kick.
- Vietnamese iced coffee, which gets its punch the same way. Vietnam grows more robusta than anywhere else.
So if you want an espresso with thick crema and a big kick, an espresso blend with some robusta is the one to buy. A 100% arabica tends to taste sweeter and smoother, with thinner crema and less kick.
"100% arabica" is not a quality stamp
Bags love to say 100% arabica. It names the species, not the quality. It tells you what kind of plant the beans came from, not how well they were grown or roasted, and a blend with robusta in it can be exactly what you want for espresso. Read it as a description, not a promise.
Common mistakes
- Thinking robusta means bad coffee. It's bitter on its own, but Italian roasters blend it in deliberately.
- Reading "100% arabica" as premium. It tells you the species, nothing more.
- Blaming the roast for the caffeine. The roast hardly changes caffeine; the species does (see light vs dark roast).
Questions people ask
Which has more caffeine, arabica or robusta?
Robusta, with roughly twice as much: about 2.2 to 2.7% of the bean's weight, against about 1.2 to 1.5% for arabica.
Is arabica better than robusta?
It's sweeter and softer. But "better" depends on the cup: robusta gives an espresso thicker crema, more body and more kick, which is why many Italian blends include it.
How can you tell arabica and robusta beans apart?
Shape and crease are the best clues. Arabica beans are longer with an S-shaped crease; robusta beans are rounder and smaller with a straight one.
Is instant coffee arabica or robusta?
Often robusta, though some instant coffee is made from arabica. Check the label.
