Roasting Racemosa

Roasting Racemosa

Racemosa is one of more than a hundred lesser-known coffee species. While Arabica (Coffea arabica) and Robusta (Coffea canephora) account for over 95% of global coffee production, dozens of wild and semi-domesticated relatives exist in small ecological pockets across Africa. Most of these are unknown to consumers, yet they represent a fascinating genetic and sensory reservoir for the future of coffee. Coffea racemosa is one of those coffees - a species that sits outside the world of Arabica and Robusta, grown in only a handful of places along Africa’s south-eastern coast.

Native to Mozambique and South Africa, Racemosa has quietly survived centuries of shifting climate, drought, and disease pressure that have challenged other species. It’s an exceptionally hardy tree - drought-resistant, tolerant of salty coastal winds, and capable of thriving in poor, sandy soils where Arabica could never take root. These traits make it genetically valuable, and they’re part of the reason plant breeders have crossed it with Arabica to produce Aramosa, a hybrid that combines Arabica’s flavour potential with Racemosa’s resilience.

Beyond its agricultural interest, Racemosa is remarkable in the cup. The beans are tiny — typically screen 10–12, only 4–5 mm wide — and they naturally contain around 0.7 % caffeine, roughly half that of Arabica. The low caffeine content gives the cup a softer, more tea-like character, while the species’ unique chemistry produces aromatics that can lean floral, herbal, and even savoury. Yet despite this potential, Racemosa has never reached commercial scale. Global production is estimated at less than 500 kg per year, harvested from just a few small farms in South Africa and Mozambique.

When a tiny lot of Natural Racemosa from Cultivar Coffee in South Africa became available through the Green Coffee Collective, curiosity took over. This was a chance to learn firsthand how an entirely different coffee species behaves in the roaster and in the cup.

First impressions

Opening the bag, the first surprise was the size: smaller than peaberries, almost seed-like. Despite their scale, the beans were very uniform and released a sweet, tropical fragrance reminiscent of passionfruit. Moisture content was measured at 10 % - similar to what would be expected from an Arabica coffee.

We had 250g available - The Aillio Bullet wasn’t suitable for such a limited amount, so the focus shifted to the Ikawa Pro 100, using four × 62.5 g batches to give a chance to iterate and improve, and explore variations in temperature and airflow.

Given Racemosa’s small bean size and low mass, heat transfer would be quicker than normal. The beans were so small there was also a concern that they would “blow over” from the Ikawa roast chamber into the collection jar at the lowest fan setting of 60%.

Roasting plan

We started with an Ikawa profile developed for sample roasting Laurina coffees, and adjusted slightly based on our expectations: 

·        Earlier key waypoints: yellowing and first crack likely to occur at lower temperatures.

·        Faster surface development: small beans brown quickly on the outside, potentially misleading visual cues.

·        Quiet or inaudable first crack: reduced bean mass means a soft, subtle expansion rather than a pronounced pop.

With those factors in mind, the first profile was designed as a cautious baseline:

·        Target first crack: ≈ 6 min

·        Development time: ≈ 30 s (≈ 11–12 %)

·        Airflow: constant 60 % (fan minimum on Ikawa)

Because the coffee was a natural process, the plan was to apply heat gently, preserving fruit character without scorching the delicate sugars that develop near the surface.

The first roast: a gentle start

The roast progressed steadily through the drying phase, but the beans were slow to colour. With temperature lowered too far, heat momentum wasn’t sufficient to drive Maillard reactions quickly, and visible browning only began after the four-minute mark.

As predicted, first crack was inaudible - more a visual cue of subtle expansion and aroma change than a sound. The roast was extended to around eight minutes before it was ended based on bean colour.

Cupping revealed a cup that was intriguing but a bit underdeveloped. The texture was light, with mint and basil aromatics and hints of unripe stone fruit - more herbal than sweet.

Refining the approach

For the second attempt, we reversed the earlier conservatism, and used the same target temperatures for yellow and first crack as for regular Arabica coffee. The fan speed was increased, starting at 70 %, reducing to 60 % at the end of the roast. The aim was to shorten the roast time to closer the initial target of 6 minutes to first crack plus 30 seconds of development time.

This minor adjustment made a significant difference. Colour changes occurred quicker, and the roast was ended after 6 minutes 45 seconds, with first crack estimated at around 6 minutes.

Results in the cup

The second roast delivered a livelier profile: medium body, gentle acidity, and a mix of peach, passionfruit, and cinnamon. The herbal notes remained - mint, basil, liquorice - but they now sat as complementary accents rather than dominant flavours.

More about the species

Fewer than 11,000 Racemosa trees are estimated to exist, with a combined annual yield under 500 kg of exportable green coffee.

The species’ resilience is one of its defining traits. It tolerates high temperatures and irregular rainfall, suggesting a potential role in breeding programs for climate adaptation. Yet this same toughness comes with trade-offs: slower cherry maturation, small yields, and a labour-intensive harvest. 

Post-harvest processing varies among the few producers who cultivate it. This lot from Cultivar Coffee was dried on raised beds in the coastal sun, followed by careful hand-sorting to remove irregular beans.

Why Racemosa matters

For roasters and coffee drinkers, Coffea racemosa offers more than novelty. It’s a reminder that coffee’s flavour spectrum extends far beyond Arabica’s familiar boundaries.

In a time when climate change threatens many traditional coffee regions, exploring alternative species has practical importance too. Racemosa’s resilience to heat and drought could prove invaluable for breeding future cultivars that maintain quality while surviving harsher growing conditions.

And then there’s the sensory side. Racemosa cups unlike anything else: delicate yet aromatic, herbal yet fruity. For those sensitive to caffeine or simply curious about coffee’s diversity, it’s a compelling experience.

We’ll be keeping an eye out for future harvests from Cultivar Coffee and other growers experimenting with this remarkable plant. For now, this tiny batch was a glimpse into coffee’s wider world and a reminder that there’s always something new to learn in the world of coffee.

References

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