Arabica vs. robusta
The two commercially dominant coffee species, and how they typically differ in growing conditions and cup character.
In short
Arabica and robusta are two different species of coffee plant, Coffea arabica and Coffea canephora. Between them they account for almost all the coffee grown commercially. Arabica is generally sweeter, more acidic and more aromatic; robusta is more bitter, heavier in body and contains more caffeine: roughly one and a half times as much on average in the largest set of measurements CoffeeHQ has read, with wide variation between coffees.
They are often presented as good coffee and cheap coffee. That is too simple. They are different crops with different strengths, and the gap between a careful and a careless example of either is wider than the gap between the species.
Robusta is one of arabica's parents
Sourced
Arabica is a natural hybrid. Genetic research has established that it arose from a cross between Coffea canephora, the species that includes robusta, and Coffea eugenioides. It carries four sets of chromosomes where its parents carry two, and unlike most coffee species it pollinates itself.
Self-pollination and a narrow founding population mean cultivated arabica has little genetic diversity, which is a large part of why it is vulnerable to disease. Robusta cross-pollinates and is far more genetically varied.
How the plants and beans differ
Tendency, not a guarantee
| Variable | Typical range | What moving it does |
|---|---|---|
| Growing conditions | Arabica: cooler, usually higher ground. Robusta: warmer, lower, more tolerant of heat | |
| Disease and pests | Arabica: susceptible, notably to leaf rust. Robusta: generally hardier | |
| Yield | Robusta is generally the higher-yielding | |
| Caffeine | Arabica: roughly 1–1.5% of the bean by weight. Robusta: roughly 2–2.7% | Approximate and variable. Caffeine is thought to help protect the plant from pests. |
| Sugars and lipids | Higher in arabica, which contributes to sweetness and aroma | |
| Bean shape | Arabica: oval with a curved crease. Robusta: rounder with a straighter crease |
General tendencies across each species. Variety, altitude and farming matter a great deal, and the caffeine figures are commonly cited approximations, not measurements of any particular coffee.
What robusta is actually used for
Widely documented
Most robusta goes into instant coffee and commercial blends, where its low cost, strength and body are the point. It also has roles it is chosen for on merit. Many Italian-style espresso blends include some, because it adds body and produces a thicker, longer-lasting crema. And it is the foundation of Vietnamese coffee, where its bitterness is balanced with sweetened condensed milk.
A small but growing number of producers now grow and process robusta with the care usually reserved for arabica, sold as fine robusta. Whether it can match good arabica is a matter of taste, but it shows that much of robusta's reputation comes from how it has been handled, not only from the plant.
What '100% arabica' does and does not tell you
CoffeeHQ explanation
It tells you the species and nothing else. Arabica ranges from exceptional to very poor, and a great deal of low-grade arabica is sold under that label. A bag that names the country, the region or farm, the variety, the process and a roast date tells you far more about what is inside than the species alone.
The species beyond these two
Sourced
- Liberica and excelsa
- Grown in small quantities, chiefly in parts of West Africa and Southeast Asia. Their classification has been revised more than once, and recent research treats excelsa as a species in its own right.
- Stenophylla and other wild species
- Well over a hundred Coffea species exist. Researchers are studying several for heat tolerance and flavour as the climate narrows where arabica can grow.
What to do next
- Arabica — The species in full: origin, genetics and where it grows.
- Robusta — The species in full, including its role in world production.
- How to choose coffee — Reading a bag for the information that actually predicts flavour.
- Caffeine in coffee — How species, dose and brewing method combine to set the caffeine in a cup.
At a glance
| Aspect | Arabica | Robusta |
|---|---|---|
| Typical growing altitude | Generally higher altitude | Generally lower altitude |
| Commonly associated acidity | Generally higher acidity | Generally lower acidity, heavier body |
| Caffeine content | Generally lower per bean | Generally higher per bean |
| Common use | Majority of speciality coffee | Common in espresso blends (for crema/body) and instant coffee |