Arabica vs Robusta: How Are They Different & Which to Use?
In nature, there are over 100 different species of coffee. Out of these species, Coffea arabica and Coffea canephora (Robusta) are the two predominant species cultivated. Coffea arabica is the most widespread species of Coffea, constituting around ⅔ of world production, while Coffea canephora (the Robusta variety) makes up the remaining ⅓ of world production. Although there are a few other species being cultivated, for instance, Coffea liberica, production is very limited, taking up less than 1% of the world total.
Let’s delve into the differences between the two most common types of coffee beans, from the plant itself to the chemical composition that gives our favourite morning beverage that unique taste.
Arabica vs Robusta: The Plant
In its natural state, Coffea arabica can reach a height of 4 to 6 meters and Robusta up to 12 meters if not pruned. However, coffee plants grown in plantations are typically restricted to 2 to 3 meters tall to boost production and for easy harvesting. Although Coffea arabica is a self-pollinating crop, bee pollination has shown to enhance the quantity and quality of yield. The Robusta coffee plant, on the other hand, is self-sterile and depends entirely on cross-pollination by wind or insects.
Arabica vs Robusta: Growing Condition
Production of superior quality coffees, particularly in terms of aroma, requires a wide temperature difference between day and night, constant alternation of wet and dry periods, and rainfall of 1500 to 2000 mm per year.
Indigenous to the highlands of Ethiopia, the Arabica is a delicate plant that requires careful tending and specific geographical and climatic conditions. It is typically grown at high altitudes to reduce the pathogenic effects of insects and fungi, which would devastate the crop at low altitudes.
Robusta coffee plants, as its name suggests, are hardier than the Arabica plants. They are relatively easier to tend to and less sensitive to insects. These lowland coffee plants grow at altitudes up to around 1000 meters and in higher temperatures.
Arabica vs Robusta: Countries of Origin
Originated in tropical Africa, the cultivation of Coffea spread over time to equatorial and other tropical regions, forming what is known as the “coffee/bean belt”. The coffee belt is a band of territories between the Tropics of Cancer and Tropics of Capricorn, where the climate and geographical conditions provide the most suitable growing environment for coffee.
While both species are grown in most regions in the belt, most of the world’s Arabica is cultivated in East Africa, Central America and South America. Central America is most noted for its quality Arabica coffees arising from the region’s geographical and climatic characteristics as well as its cultivation methods. Popular origins include Brazil, Colombia, Guatemala and Ethiopia.
Robusta coffee plants are mainly cultivated in South-East Asia and Africa. Vietnam is now the world’s largest exporter of Robusta coffee. Indonesia is the second most important coffee producer in the Asian economy, producing mainly Robusta. The island of Hainan and Yunnan province in China also cultivate Robusta only.
Arabica vs Robusta: Look of the Bean
Arabica produces bigger, elongated beans with a curved crease in the middle of the bean. Robusta beans are smaller and rounder with a less curved or almost straight crease. Before roasting, Arabica beans are light green while Robusta beans are pale green.
Arabica vs Robusta: Chemical Composition
Arabica was created by a spontaneous crossing of two species, which contributes to the rich genetic makeup with 44 chromosomes, double that of Robusta. This translates into a coffee with much more aromatic compounds than the Robusta. In addition, Arabica contains more lipids and trigonelline, while Robusta contains more caffeine and chlorogenic acids.
Caffeine is the most known and well-studied compound found in coffee. Robusta contains almost twice as much caffeine as Arabica, with about 100 to 140mg per cup of espresso, as compared to 60 to 80mg of Arabica. The higher concentration of caffeine in Robusta acts as a natural pesticide, which explains why the plant is more resilient to pests and diseases than Arabica.
Arabica vs Robusta: Flavour Profile
Although Robusta is more robust as a plant, the tastes of the beverages it produces are typically considered more inferior compared to Arabica. Arabica presents intense, fruity and floral notes with a tint of sweetness and citric acidity while Robusta produces a much less aromatic coffee with a markedly earthy, woody and bitter taste. Robusta has widely been used in instant coffee and espresso blends to provide a strong crema and extra caffeine. However, there has been an emerging trend of specialty or fine Robusta coffee recently that is trying to change its bad rep of it being a “cheaper” or “lower quality” coffee.
Arabica vs Robusta: Roasting
Because of the differences in chemical composition, the roasting approach also varies. Robusta beans have a lower density and a more rigid cellular structure. Therefore, heat transmission within the bean is not the same, and the final roasting temperature can be 5 to 7℃ higher than Arabica. Robusta coffee is typically roasted to a darker roast in order to counteract the bean’s natural bitterness whereas Arabica beans can be roasted to various degrees to yield different results depending on the desired flavour profile.
Which Bean to Use?
Each brewing method has its pros and cons and differs in the way they extract flavours. Here are some recommendations of which type of bean to use.
Arabica beans are used in many brewing methods because the sweeter notes are most popular among coffee drinkers. However, that doesn’t have to be the only option. Espresso can be brewed with either Arabica and Robusta or a mix of both. While Arabica beans with a strong body produce more complex flavour profiles, Robusta is known to produce a thicker crema on the espresso. The caffeine-heavy Robusta is great for those looking for a stronger kick in the morning. Milk-based coffees like Flat White can work with both types of beans depending on the preference for flavours. Vietnamese coffee uses condensed milk to balance off the bold and bitter taste in Robusta. Single-origin Arabica generally works better in cold brew because the beans’ more subtle, fruity flavour profiles can get picked up well in this method.
At the end of the day, coffee drinking is a very personal experience. There is no right or wrong way to drink coffee. At illy, all our products use Arabica beans to deliver intricate notes and more complex flavour and aromatic profiles. Discover our range of Arabica coffee products today.