Arabica and Robusta

In this article, we will talk about Arabica and Robusta—this is basic knowledge that every barista should have.

Out of more than 125 known coffee species (with some sources mentioning over 300 described types), only two are commonly used by humans: Arabica and Robusta. They account for 99% of global coffee production—60–70% of it is Arabica and 30–40% is Robusta. This percentage fluctuates depending on the yield of each type in a given year.

How can Arabica and Robusta beans be visually distinguished?

Arabica beans are usually more elongated with an S-shaped central crease. Robusta beans typically come in two shapes: round or teardrop-shaped (round on one side and slightly pointed on the other), and they have a straight, even crease. If you place the beans on a flat surface, Arabica beans will be slightly concave, while Robusta beans usually lie flat. Using these simple characteristics, you can visually identify about 80% of beans.

Let’s look at a comparative overview of the two types

Origin

Coffee originates from Africa. Scientists debate the exact location—most agree it's Ethiopia, but some claim it’s actually from neighboring Sudan. In any case, it definitely comes from East Africa. Arabica was discovered first, somewhere in the Ethiopian region. Fun fact: Kenya, which borders Ethiopia, only received coffee in the late 19th century.

Climate zones

Coffee grows in subtropical and tropical zones. In Russia, the upper subtropical region is Sochi, but coffee doesn’t grow naturally in Russia—it’s too cold.

Altitude

Arabica grows at 900–2100 meters above sea level, while Robusta grows at lower altitudes—200–900 meters. Arabica trees can grow 3 to 6 meters tall, and wild Robusta trees can reach up to 12 meters. However, in agriculture, trees are always trimmed. There are two reasons for this:

• To ease harvesting: coffee often grows on steep slopes, and shorter trees are easier to harvest.

• To stimulate yields: trimming is perceived as a stress signal, and the tree puts more energy into fruit production.

Root systems

Arabica has a deep vertical taproot that can reach up to 2.5 meters, with additional coaxial and surface roots. Robusta has more shallow, surface-level roots.

Content of oils, sugars, and caffeine

Arabica is richer in sugars and oils but contains less caffeine. Robusta, in contrast, has slightly more caffeine. Many mistakenly believe we love coffee for the caffeine, but it’s actually the sugars and oils that make it pleasant. Caffeine acts as a defense mechanism for the tree. Interestingly, most of the caffeine is found in the skin of the coffee cherry, not the bean. While caffeine is indeed a stimulant, its actual impact is questionable—perhaps it’s more placebo than anything.

Yields

Yields depend on the type and variety, ranging from 500 grams to 5 kg of cherries. Robusta usually has a higher yield.

Regions

Arabica is cultivated in Central and Eastern Africa, and Central and South America. Robusta is grown in Asian countries and Western Africa. Brazil grows both Arabica and Robusta.

Changes during roasting

Coffee has three basic flavor profiles: acidity, sweetness, and bitterness. Acidity and sweetness develop during roasting and peak at a certain point. If roasting continues beyond this point, sweetness and acidity decrease, and bitterness increases. Eventually, the bean becomes so dark and dry it can be crushed with fingers. Brewing such beans yields a yellowish liquid rather than the typical brown, because extreme roasting destroys all compounds—including those responsible for bitterness.

External factors affecting freshness and flavor post-roast

These include oxygen, temperature, and humidity. Their interaction with coffee during storage should be minimized. Also, how coffee ages depends on roast level, porosity, and surface area—i.e., how finely it’s ground. The greater the surface area, the faster the degassing, and the faster the coffee ages.

Flavor differences between Arabica and Robusta

Arabica has higher sweetness and lower bitterness, and the resulting beverage is less dense. Robusta has lower sweetness, higher bitterness, and more intense tactile sensations.