Exploring Unusual Coffee Species

Most coffee drinkers are familiar with two coffee species, Arabica (Coffea arabica) and Robusta (Coffea canephora), which dominate global production. However, many other wild coffee species exist, often growing in remote African forests or other tropical regions.

This month we tasted the ‘Future Coffee’ tasting kit by Plot Roasting, which contained samples of three unusual coffee species – a racemosa, eugenioides and excelsa. Interestingly each of these species are also lower in caffeine.

After we tasted the coffees we did a bit of research to learn more about the history (and future?) of these three unusual coffee species.

The Common Coffee Species

Arabica and Robusta are the two most commonly cultivated coffee species. Arabica is native to the highlands of Ethiopia and South Sudan and today accounts for roughly 60–70% of global coffee production. Arabica plants prefer high elevations with cooler temperatures and ample rainfall. The beans tend to have complex flavours with higher acidity and aroma. Arabica coffees generally contain about 1.4-1.6% caffeine by weight, which is relatively moderate among coffee species.

Robusta originated in central and western sub-Saharan Africa and now makes up around 30–40% of world coffee production. As the name suggests, Robusta is a hardy plant - it tolerates hotter climates, lower altitudes, and is resistant to many pests and diseases that affect Arabica. Robusta yields more coffee cherries per tree and is easier and cheaper to cultivate, which is why it’s widely used in commercial blends and instant coffee. The flavour of Robusta coffee is typically described as strong, earthy, and bitter, with lower acidity. This harsher taste is partly due to a higher caffeine content – about 2.2% (nearly double that of Arabica). Caffeine acts as a natural pest repellent, so Robusta’s extra caffeine helps the plant survive but also contributes to a more bitter brew.

Racemosa (caffeine content = 0.5%)

Our cupping observations: Herbal, savoury

Coffea racemosa is one of the world’s rarest coffee species. It is endemic to a small coastal region of southeastern Africa, primarily the sandy forests of northern South Africa and southern Mozambique. In the wild it grows as an understory shrub in dry forest conditions. Racemosa was briefly cultivated commercially: during the 1960s and 70s, Portuguese plantation owners in Mozambique grew racemosa as a coffee crop.

In appearance, racemosa is a small tree usually no taller than 3 -3.5 meters. It has small, narrow leaves and produces white, fragrant flowers. Notably, the plant often bears blossoms and ripe fruits simultaneously, which means cherries do not all ripen at once. This trait necessitates careful hand-harvesting of individual cherries over time - one factor that makes racemosa labour-intensive and low-yielding. In fact, racemosa’s productivity is a major challenge: one report noted it can take six Racemosa trees to produce the same weight of coffee beans as a single Arabica tree. This very low yield, combined with the tiny bean size, has limited its attractiveness to farmers.

Common taste descriptors for racemosa include earthy and spicy.

Racemosa’s climate resilience has renewed interest in racemosa cultivation. Racemosa is (comparatively) drought and heat tolerant, and thrives in hot, dry climates. As climate change threatens traditional coffee-growing regions with higher temperatures and sporadic droughts, Racemosa’s resilience is a promising trait.

Racemosa has already been cross-bred with Arabica to create the coffee hybrid Aramosa – combining Racemosa’s climate tolerance and low caffeine with Arabica’s higher yield and flavour quality.

Eugenoides (Caffeine content = 0.5%)

Our cupping observations: intensely sweet, ripe tropical fruit

Coffea eugenioides is a fascinating coffee species for several reasons. It is indigenous to the highlands of East Africa, with native populations in countries such as the Democratic Republic of Congo, Rwanda, Uganda, Kenya, and western Tanzania. In the wild it grows at high elevations and in shaded environments, somewhat similar to Arabica. Eugenioides holds a special place in coffee history: it is one of the two parent species of Arabica. (Arabica originated as a hybrid between eugenioides and robusta in Ethiopia). Despite this legacy, eugenioides itself was never widely cultivated as a crop.

In recent years Eugenioides has been “rediscovered” by specialty coffee enthusiasts. A notable moment was in 2021, when several competitors in the World Barista Championship used eugenioides coffee in their presentations. The source of these eugenioides beans was Finca Inmaculada in Colombia, which cultivated a small lot of eugenioides trees and applied experimental processing techniques to bring out the best in the cup. These efforts showed that even though eugenioides is very low-yielding and finicky to grow, it can produce a remarkable beverage when handled with care.

Similarly to racemosa, eugenioides plants are delicate and produce far fewer cherries per tree than Arabica. This makes eugenioides risky and not economically attractive in a conventional sense – a farmer would get only a small fraction of the coffee yield from the same area compared to Arabica. Today, there are just a few places cultivating it, mostly for research or ultra-specialty micro-lots.

Eugenioides beans produce a brew with unusually high sweetness and almost no bitterness. Cupping notes commonly mention the unusually high sweetness.

Eugenioides is likely to remain a rare delicacy rather than a mainstream crop. Its agricultural drawbacks (fragile trees, low yield) mean that farmers would need a very high price incentive to grow it - which limits it to the realm of specialty coffee sold at a premium. Nonetheless, eugenioides holds significant value for coffee science and breeding. As one of Arabica’s parent species, it carries genes that contributed to Arabica’s success. Plant breeders and researchers are interested in eugenioides to see if it harbors useful traits (for example, disease resistance or drought tolerance genes that Arabica might not have fully expressed). Its outstanding cup quality also raises interesting possibilities: could some of those sweet flavour attributes be bred into new Arabica hybrids or other species? World Coffee Research, has included eugenioides in trials to explore its potential in breeding programs. And on the consumer side, the buzz created by eugenioides in competitions has created a small but real demand - specialty roasters now sometimes offer eugenioides coffee in very limited releases for curious customers willing to try an unusual cup.

Excelsa (Caffeine content = 0.9%)

Our cupping observations: sweet, pineapple

Excelsa coffee is an unusual case because for much of its history it was not even considered a separate species. Excelsa was first documented in 1903 in central Africa (near Lake Chad) by botanist Auguste Chevalier, who classified it as Coffea liberica var. dewevrei, essentially treating it as a type of Liberica coffee. The Excelsa plants share some characteristics with Liberica – notably, they are large, vigorous trees with big leaves and can grow over 10–15 meters tall. For decades, coffee science grouped Excelsa with Liberica, and many farmers and traders simply thought of it as a Liberica variant. However, more recent analyses of genetics and plant traits suggest that Excelsa is distinct enough to be its own species. 

Today, Excelsa is grown in small quantities in parts of Southeast Asia and Africa. It is mainly found in Vietnam, the Philippines, Indonesia, and Uganda, usually on a very localized scale. The trees thrive in warm, tropical climates and do well at medium elevations (~1,000–1,300 meters above sea level). An Excelsa tree is impressively large and high-yielding – when mature, it can produce a great number of fruits. But its height (often 15m or more if unpruned) makes harvesting difficult, as farmers need equipment to reach the cherries. In regions where it’s grown, farmers sometimes graft Excelsa onto shorter rootstock or prune aggressively to keep trees manageable. Excelsa, like Liberica, is hardy: it shows good resistance to diseases and pests and can handle hot conditions that would stress Arabica. This resilience is a point in its favour for future cultivation, especially as climate change pressures increase.

In terms of caffeine, Excelsa falls into a middle ground among coffees. Measurements show Excelsa beans typically contain around 0.9% caffeine by weight, which is lower than most Arabica, but not as extremely low as Racemosa or Eugenioides.

Because Excelsa trees are vigorous and resilient, they could be a good candidate for climate-resilient farming in regions where Arabica struggles. Its tolerant nature means it can grow in hot, lowland environments where others might fail.

If you are looking for a naturally lower caffeine brew check out our low caf coffees.

References

1. Davis, A. P., et al. (2021). Hot Coffee: The Identity, Climate Profiles, Agronomy, and Beverage Characteristics of Coffea racemosa and C. zanguebariae. Frontiers in Sustainable Food Systems.
2. Excelsa Coffee International (2025). Excelsa Coffee: The Case for Its Recognition as an Independent Coffee Species.