The Great Debate: Charting the Future of Coffee Species at ICC 2024
By Dr Kenny Lee Wee Ting (Originally published in Chinese: 《ICC 2024 論壇上咖啡物種學的路線之爭》)
An Academic Showdown in the Coffee World
The International Coffee Convention (ICC) has evolved at a pace that's frankly exceeded my expectations. In just a decade, it has transformed from its predecessor, the Stuttgart Coffee Summit, into arguably the most influential academic forum in the coffee sphere. The contributions of Dr. Steffen Schwarz and Dr. Dirk Lachenmeier in this journey have been immense.
When I say academic forum, I’m referring to a platform for serious, peer-reviewed research – not commercial competitions or casual gatherings. This makes it a niche within a niche. To give you a sense of the caliber, let me highlight some of the committee members and key scholars present at ICC 2024 (in no particular order):
Dr. Steffen Schwarz: Founder of Coffee Consulate.
Dr. Aaron P. Davis: The renowned coffee botanist from Kew Royal Botanic Gardens, who has named over 40 of the 130 known coffee species.
Dr. Christophe Montagnon: Former Chief Scientist and founding member of World Coffee Research (WCR).
Dr. Vanusia Nogueira and Max Fabian: Current and former heads of the International Coffee Organization (ICO).
Dr. Dirk Lachenmeier: German coffee scholar.
Holger Preibisch: President of the German Coffee Association.
Romain Guyot: French coffee species geneticist.
Beyond these names, numerous other academics from international research institutions and universities, specializing in coffee sustainability, coffee and health, sensory science, and more, were present. Opinions often diverged, and the intellectual sparring was palpable – a true "Huashan Lunjian" (a legendary contest of masters from Chinese wuxia fiction) for the coffee academic world.
Condensing two days and 16 hours of fascinating notes into a single post is impossible (that would take at least 24 articles!). So, I'll offer a somewhat eclectic, high-level overview, touching on key points without always naming specific speakers. For those keen on a deep dive, all conference papers are available for download on the ICC website, with videos of each presentation to be released in a few weeks.
Two Paths: Can They Converge?
Unsurprisingly, the major themes at this ICC centered on the "threat of climate change" and "inter-species coffee research." Most other topics could be considered sub-themes or footnotes to these two pillars.
On the sustainability and climate change front, scholars aligned with the ICO presented a wealth of valuable data and perspectives.
However, when it came to how coffee botanical research should respond to climate challenges, a clear division emerged among the academics:
The Traditional Route: This camp focuses on improving Arabica for greater resilience, whether through selective breeding or hybridization. Their research and data largely centered on Arabica and its close relatives (often termed 'Arabicoid' coffees).
The "New Frontier" Route: This group advocates for looking beyond Arabica sooner rather than later, urging the exploration of entirely different coffee species as a more robust long-term solution.
The leading voice for the latter is undoubtedly Dr. Aaron P. Davis. Drawing on extensive adaptability data for "other" coffee species, he argued pointedly that even so-called "purebred" Robusta (Canephora) isn't immune to extreme climate impacts. If Robusta itself isn't robust enough, he questions the wisdom of pinning hopes on Arabicoid varieties that seek to gain a mere fraction (1/2, 1/4, or less) of its genetic advantages through hybridization.
Speaking of Robusta (Canephora), research by Dr. Christophe Montagnon highlighted that, genetically, Canephora should actually be divided into four major lineages: Guinea, Nana, Conilon, and Robusta, each having spread to different coffee-producing regions globally.
For those championing the optimization of Arabica, the natural hybrid of Arabica and Canephora – the Hybrid de Timor (HdT), a triploid (Editor's note: corrected from an initial mention of tetraploid during the forum, thanks to Shao Bo from Taiwan) – is seen as a game-changing variety. HdT, possessing valuable rust-resistance genes, can be crossed with Arabica to parent "mother line" coffees like Catimor and Sarchimor. It's no exaggeration to say HdT's discovery fundamentally altered coffee cultivation history by combating leaf rust.
But history is past. Today's challenges aren't primarily leaf rust, but rather the extreme heat, cold, droughts, and floods brought by climate change.
An interesting audience question arose regarding HdT: why has this natural hybridization seemingly only occurred on the island of Timor over so many years? Dr. Montagnon offered a fascinating perspective: such inter-species hybridization in nature isn't actually rare; we just usually don't "see" it. HdT was discovered because leaf rust and other coffee diseases were widespread globally much earlier than the mid-19th century, as commonly documented. Early coffee exports from Ethiopia and Yemen were predominantly a single Arabica variety, leading to dangerously low genetic diversity. When disease struck, entire plantations would yellow and die, making any resistant individual plants (like HdT) stand out dramatically – a "spot of green in a sea of yellow." In reality, many other natural coffee hybrids likely exist unnoticed within plantations. This insight from Dr. Montagnon was truly thought-provoking.
The Striking Advantages of Inter-Species Coffee
This brings me back to Dr. Aaron Davis's core arguments for embracing inter-species coffee:
HdT's Waning Edge: As mentioned, under new climate pressures, the advantages of HdT-derived lines are diminishing. The "mother-line era" may be ending. He posits that every species has its evolutionary limits; expecting one to develop traits far beyond its natural adaptive range is an inefficient endeavor.
The Dilution Dilemma: Many Arabicoid coffees, born from crossing Arabica with other species, are repeatedly backcrossed with Arabica to improve flavor. While flavor might improve, these varieties lose their original genetic advantages for environmental resilience. This research direction risks achieving neither goal effectively and wasting precious time. Take Aramosa, for example. Originally a Brazilian hybrid of Coffea racemosa and Coffea arabica aimed at drought resistance. Wild African C. racemosa is incredibly drought-tolerant, thriving in sandy soils and surviving nearly six months without rain, producing a spectacular "tree full of white blossoms." Today, however, some coffees still called Aramosa may contain less than 20% racemosa genes due to continuous backcrossing, significantly reducing their drought tolerance.
Other Diploid Coffees Can Be Delicious: Dr. Davis is a world-renowned expert on Excelsa and Stenophylla (narrow-leaved coffee), with his team leading much of the academic research in this area for over two decades. According to repeated tests by him and several CQI sensory experts, Stenophylla – which can tolerate temperatures 6°C higher than Arabica and grow at hot, low altitudes of 200-300 meters – tastes remarkably like a Bourbon Arabica in blind cuppings. It often exhibits distinct citrus notes and scores 83+ points. Many cuppers even mistake it for Arabica, shattering the conventional wisdom that good coffee only comes from high altitudes. Similarly, properly processed Excelsa can easily score 84+ points. Indeed, some Liberica types we are working with also score above 83. I say "types" because we believe C. liberica and C. dewevrei (Excelsa) are distinct species, and many coffees currently lumped under "Liberica" likely warrant classification as separate species. An additional issue: Excelsa has long been mixed with Robusta in Africa, India, Laos, Vietnam, and Indonesia. Eight years ago, I tasted a Robusta lot from Uganda that was overwhelmingly full of Liberica's tropical fermented fruit notes – it tasted nothing like Robusta. It likely contained a high percentage of Excelsa/Liberica. This raises an awkward question: when grading Robusta, how can you be sure it's not blended with Excelsa?
The Yield King - Excelsa's Ace: Perhaps most importantly, Excelsa has an astonishing natural advantage: its productivity. A well-tended Excelsa tree, even without any fertilizer, can yield up to 70 kg of cherries. Assuming a 1:10 cherry-to-green-bean conversion ratio, that’s a potential 7 kg of green beans per tree! This leaves Arabica and Robusta miles behind.
The Farmer's Reality: Faced with global warming, the coffee industry typically considers three responses: 1) Move cultivation to higher altitudes. 2) Implement advanced farming techniques. 3) Switch to climate-resilient coffee varieties. When downstream industry players talk glibly about farmers moving to higher altitudes, they often forget a fundamental issue: land ownership. Farmers are tied to their land. If the higher-altitude land isn't theirs, how can they relocate? Moreover, the vast majority of coffee farmers are not wealthy (many live below the poverty line) and simply cannot afford to invest in new production technologies. This leaves variety change as the most viable, and increasingly urgent, path forward. During one of the conference's cupping sessions, we tasted a sample of Coffea zanguebarica from Mozambique. Besides a distinct herbal, medicinal note (reminiscent to us Chinese of Wanglaoji, a traditional herbal tea), it showed great potential in sweetness, aroma, and body.
The Muddle in Variety Research
The confusion in species classification isn't limited to inter-species research. In his keynote presentation, "Democratising Coffee Genetics: Outcomes of the 'Coffee Genetic Discovery' Project," Dr. Christophe Montagnon delivered a bombshell for Arabica enthusiasts. Their team's years of genetic research, in collaboration with WCR, COE, SCA, and others, revealed that of all Arabica samples received from commercial growers, only 64% could be genetically confirmed as the claimed variety. In other words, 36% of farmers claiming to grow Gesha/Geisha weren't actually growing Gesha. The misidentification rate for Typica and Bourbon was even more alarming: only 19% of samples claimed to be Typica or Bourbon were genetically verified as such; a staggering 81% were not. Let that 19% sink in. Without access to such genetic data, the validity of much "research" conducted on these varieties over the years is significantly compromised. Dr. Montagnon called for institutions to collaborate on a "shared coffee gene bank," arguing it would ultimately benefit all researchers. On a brighter note, the same study, analyzing numerous COE competition beans, confirmed that altitude does indeed add significant value to coffee flavor – an average increase of 1 point for every 500-meter rise in elevation. Furthermore, Gesha demonstrated a clear 2.14-point advantage over other varieties in competition, while Pacamara showed a 0.96-point advantage.
Could Malaysia Have Wild Coffee Species?
Another point that caught my attention was a map presented by a group of experts from a major European coffee research nation. This map, showing the distribution of the 130 known coffee species, indicated almost all originated from Africa and Madagascar, with only two or three from Asia and Oceania. This is clearly incorrect. This detail surprised me, as this nation boasts several renowned coffee research centers and the world's most comprehensive Arabica conservation collection. Yet, they failed to verify such conspicuous data. It shows that even experts can err when stepping outside their specific domain. To avoid singling anyone out, I'll discuss this discreetly. According to Dr. Aaron Davis's team, while the majority of the 130+ known wild coffee species are indeed found in Madagascar, surrounding islands, and continental Africa, several species originate from India, Southeast Asia, and Australia. Myanmar, Thailand, Cambodia, Java, Papua New Guinea, Australia, and Malaysia all have native wild coffee species. Yes, you read that correctly – Malaysia is home to one of the 130 known coffee species. As this relates to our future collaborative research projects, I can only hint at this for now, with a more formal announcement to come.
Another intriguing question: why are over half of all coffee species found in Madagascar and its surrounding islands, which also boast the highest number of "caffeine-free coffee species"? Does this mean the Malagasy region is the true origin of coffee? I specifically asked Dr. Davis about this. His conclusion was the opposite of what I might have expected. Genetic lineage studies show that all 60+ known coffee species from the Malagasy islands actually evolved from a single ancestral coffee plant that migrated from continental Africa. The diverse and varied environmental pressures on the islands accelerated the evolutionary divergence of this single ancestor, resulting in the multitude of species we see today – a fascinating evolutionary phenomenon.
In Conclusion
The above is a brief summary compiled during my return journey, merely scratching the surface of this incredibly rich forum. There's so much more I'd like to write about, including other researchers' exciting frontier findings and industry chatter about WCR's alleged decline due to talent drain. These will have to wait until I have more time.
As for my own stance in this "battle of the paths," my research direction presented at the forum likely makes it clear without explicit statement. It was a privilege to witness the "gods" of the coffee academic world showcase their incredible work, and we younger researchers learned immensely.
As Coffee Consulate's coordinator and head of education for the Asia-Pacific region, I also collaborate closely with Dr. Aaron Davis on several long-term research projects. My initial coffee samples were, in fact, sequenced and identified with the help of Dr. Christophe Montagnon. Perhaps due to these relationships, I find myself strongly agreeing with aspects of all their perspectives.
From my long-term exchanges with these leading figures, I believe their visions, while distinct, are all profoundly insightful, and these two research directions can be integrated. Who knows? Perhaps one day we'll discover a highly adaptable non-Arabica species that can be perfectly combined with Arabica to develop the "perfect coffee" – one that simultaneously solves the challenges of adaptation, flavor, and yield.
A diversity of approaches within any research field is always a good thing.
(Note: Special thanks to Shao Bo from Taiwan for correcting a detail mentioned during the forum – HdT should be considered a triploid.)