Climate change poses an existential threat to the future of coffee; as temperatures go up (and weather patterns become less predictable), lands once suitable for production no longer are. To combat this, researchers and producers have three different options for the continuation of coffee cultivation: moving where coffee is grown to areas now more suited for it (follow the shifting Coffee Belt), adapt farming practices, or plant new, more resilient varieties. The first two options are generally viewed less favorably for the significant disruption they would cause, leaving the third, utilizing different varieties, as arguable the most viable.
And now, researchers are giving new eyes to an old coffee species that may just be ready to help bolster global production. Excelsa, a Liberica varietyโthat third species behind Arabica and Canephora (robusta)โis showing promise for its production, resilience, and flavor profile.
In a new study published in the journal Nature Plants, lead author and renowned coffee researcher Dr. Aaron Davis of the Royal Botanic Gardens, Kew examines two varieties of Liberica currently growing in Africa: C. liberica var. liberica and C. liberica var. dewevrei. Once thought to be entirely different species due to the difference in size of the cherries produced, the two varietiesโmore commonly referred to as liberica and excelsa, respectivelyโcame to be understood as part of C. liberica. Excelsa, in particular, is believed by Dr. Davisโs team to be especially noteworthy.
Once popular around the turn of the 20th centuryโโ[sitting] alongside Arabica as the main coffee species of global commerce,โ per the studyโliberica has a list of attributes that many find interesting to deal with modern coffee production issues. It is robust, high-yielding, with the fruit staying on the tree when ripe (instead of falling to the ground), it grows well in warm, lowland locations (<1,000MASL), and it is believed to have pest and disease resistance and drought tolerance. But, as Dr. Davis et al. note, it did not taste good. Though, this may be chalked up to the improper post-harvest processing due to the large size of the cherriesโroughly the size of plums with a thick outer skinโthat led to improper drying.
Excelsa, per the study, has many of the same positive attributes of liberica, but with some key characteristics that make it a promising candidate for greater acceptance. Like liberica, excelsa has been shown to have high yields, sometimes exceeding those of Arabica and robusta. But excelsa also exhibited โsynchronous fruit ripeningโ and โtightly clustering fruits at the leaf nodes,โ both of which make harvesting easier. Perhaps the largestโor notโpositive attribute is the size of the cherry. Exelsa cherries more closely resemble those of Arabica, with a much thinner skin and softer pulp, allowing for a much easier post-harvest processing that doesnโt require any special machinery.
And it bears out in the flavor profile. Modern flavor assessments of excelsa grown in Uganda and South Sudan have been said to have a โmild, smooth, pleasant-flavored coffee of low to medium acidity and low bitterness,” with tasting notes that include cocoa nibs, peanut butter, dried fruits, Demerara sugar, maple syrup raspberry coulis, figs, plums, and milk chocolate.
โIn terms of its cup profile, excelsa coffee sits much closer to Arabica, compared to robusta. When properly harvested and processed, itโs sweet and smooth, of low to medium acidity, with notes of a range of different fruits, chocolate and caramel,โ Dr. Davis tells Sprudge. โI donโt think we have yet seen the full sensory potential of this coffee, although itโs probably not going to have the complexity of the best Arabicas.โ
The potential for excelsa is more than theoretical. In Uganda in particular, 200 farms are currently growing the variety, with the number continuing to climb year after year. As the study notes, the switch has been farmer-led and is resulting in many to switch from growing robusta to excelsa, some exclusively.
โThereโs still so much we donโt know about excelsa, as itโs been largely neglected as a coffee crops species,โ Dr. Davis states. But still, the prospect of a reinvigorated variety of coffee from a species completely separate from the traditional Arabica and robusta, that is right now approaching commercial viability AND is finding increased appeal, itโs an exciting development. If successful, it may open up where higher quality coffee can be grown as well as provide a means to maintain production in current growing lands being threatened by climate change.
Zac Cadwaladerย is the managing editor at Sprudge Media Network and a staff writer based in Dallas.ย Read more Zac Cadwaladerย on Sprudge.
All images via Dr. Aaron Davis, used with permission
