The Natural Process: Harnessing Fermentation for Intense Fruit Profiles
Estimated read time: 7 minutes - Last updated 25/02/2026
In the roastery, we see natural (dry) processing as the ultimate test of patience. Unlike washed coffee, where fruit is removed early, naturals dry with the whole cherry still on the seed. That means weeks of controlled drying and fermentation influence before hulling (removing the dried fruit skin), and it is exactly why naturals can taste so fruit-forward and wild when they are done well. At Wrexham Bean, this is the profile we lean into with coffees like African Moon.
What is the natural coffee process?
The natural process, also known as the dry process, is a method where coffee cherries are dried whole with the fruit and skin intact. Unlike the washed process, which removes the fruit before drying, the natural process allows the bean to ferment inside the cherry for several weeks. This results in a heavy-bodied cup with intense fruit-forward flavours like strawberry, blueberry, and tropical fruit.
Natural Process Quick Stats
- Process name: Natural / Dry Process
- Primary flavours: Tropical fruit, berries, chocolate, wine-like notes
- Body: Heavy to syrupy
- Acidity: Usually low to medium in perception
- Roaster note: Often high solubility in the cup, so start slightly coarser than your washed recipe
Natural coffee cherries are dried whole on raised beds, letting fruit contact shape the final cup profile.
The Raw Truth: What Happens on the Drying Bed
Natural process coffee is dried with the full cherry intact, then milled after drying. This is one of the oldest processing methods and still one of the hardest to execute consistently at a speciality level. The speciality processing review in Beverages (MDPI) highlights the same point we see in practice: naturals can be outstanding, but they are high-risk because cherries are exposed longer, and defects can escalate quickly if drying is poorly managed.
This is why good naturals need disciplined sorting, airflow, regular turning, and moisture control. One bad pocket on a bed can throw the cup.
Brix & Biology: The Science of Sugar Migration
The flavour intensity in natural coffee is biochemistry (who would have thought coffee could be so technical). As cherries dry, mucilage sugars become more concentrated and microbial metabolism reshapes flavour precursors. An integrative review in the International Journal of Food Science & Technology describes how fermentation transforms compounds that later drive aroma and taste in the cup.
The Specialty Coffee Association’s fermentation effect explainer also notes that fermentation during dry processing happens in the outer cherry layers, with some metabolites persisting as a signature through to green coffee.
This means that the coffee bean is effectively marinating in a changing fruit environment during drying, which is why natural coffees can taste jammy, winey, or tropical in a way washed coffees usually do not.
Fermentation during drying is where natural coffees build their fruit-heavy identity.
At the Drum: Why Roasting Naturals Is a High-Stakes Game
Naturals can roast beautifully, but they are unforgiving if you apply heat carelessly, and this is what coffee roasters like ourselves need to consider. Because of fruit-derived compounds and uneven surface behaviour from processing, naturals are more prone to tipping and scorching if you hit them too hard, too early.
We treat them with controlled energy and careful curve management through Maillard and development. The point is to caramelise and build sweetness without burning away fruit esters. Research on Maillard reaction product development during coffee roasting reinforces the same principle: heat application profile shapes flavour chemistry, not just roast colour.
High-Altitude Naturals vs Low-Altitude Naturals: Why They Roast Differently
The same precharge does not mean the same roast outcome. In natural-process coffees, altitude changes bean structure before you even load the drum. Research on arabica across elevation bands shows that altitude can shift bean chemistry and physical quality, while work on natural-style fermentations shows that altitude also shifts microbial activity and volatile precursors. In parallel, field data from Gorongosa found that higher elevations were associated with higher bean mass/apparent density and delayed harvest timing, which is exactly the kind of structural change that alters heat uptake in roasting coffee.
At the cup level, altitude-linked chemistry differences are now well documented, showing that higher elevations can shift the balance of flavour precursors and sensory outcomes, including aroma/flavour lift in cupping, as shown in recent altitude-flavour precursor work. For natural coffees specifically, that can mean very different fruit expression from the same process label.
Roast implication: when density/thermal properties differ, you must change how energy is delivered. Work on coffee thermophysical behaviour shows density, porosity and heat-transfer properties evolve and directly affect roast dynamics, not just colour change (Journal of Food Engineering). And roast-profile research confirms that changing time-temperature curves materially shifts acidity and flavour outcomes (Scientific Reports).
| Roast variable | Higher-altitude naturals (typically denser) | Lower-altitude naturals (typically less dense) |
|---|---|---|
| Heat uptake | Slower core penetration, needs stronger early energy to avoid a hollow centre | Faster surface response, easier to overshoot early and mute sweetness |
| Gas application | Higher initial gas can be useful, then taper to protect volatile fruit notes | Gentler initial gas, smoother ramp through Maillard to avoid harsh edges |
| Airflow strategy | Increase airflow progressively as the exothermic phase builds | Bring airflow in earlier to control surface temperature and smoke load |
| Development pacing | Protect acidity/florals with controlled finish; avoid over-extending post-crack | Long enough to build body/chocolate, but avoid baked flattening from slow, low-energy finishes |
So when we roast coffee, saying that they're “both natural” is not enough information for us. Altitude changes fermentation ecology, precursor chemistry, density and thermal response, and that means precharge is only one lever. The final flavour is set by the full curve: charge, gas cadence, airflow timing, and development control.
The Roaster’s Challenge: African Moon vs Brazilian Eagle (Both Natural, Not the Same Roast)
As we covered in the high-altitude vs low-altitude section above, altitude changes bean structure and fermentation expression, so we do not treat all naturals as one roast style. That is exactly what we see with African Moon (Uganda, 1400-1800 m.a.s.l.) vs Brazilian Eagle (Brazil, 800-1300 m.a.s.l.). Both are natural-process coffees, and both start at 230°C precharge, but African Moon takes energy differently in the drum. We run stronger early energy to penetrate the denser structure, then soften the finish so the fruit and floral top notes stay clean instead of getting flattened by overdevelopment.
Brazilian Eagle behaves differently. At a lower altitude with a more sugar-forward, faster surface response, it is easier to scorch if treated like a denser high-grown natural. So we use a gentler post-charge ramp with a longer browning phase to build chocolate, nut sweetness, and syrupy body without harsh roast edges. Meaning, the same process label and same starting precharge, but different gas, airflow, and development pacing because each coffee’s structure and chemistry ask for a different roast strategy.
| Roast factor | African Moon (Uganda Natural) | Brazilian Eagle (Brazil Natural) |
|---|---|---|
| Altitude (m.a.s.l.) | 1400-1800 | 800-1300 |
| Structure | denser high-grown response | faster surface heat response |
| Precharge | 230°C | 230°C |
| Early roast energy | Higher early push to avoid an underdeveloped core | Gentler early application to avoid tipping/scorching |
| Mid/late curve strategy | Controlled taper and cleaner finish for aromatic lift | Longer browning emphasis for body and cocoa depth |
| Roast time/weight loss | 15:30 / ~15% | 16:30 / ~14.8% |
| Cup outcome | Dark chocolate, cherry, toasted nuts with brighter top-note clarity | Heavier chocolate-nut body with deeper dried-fruit sweetness |
This matches what roasting science shows: changes in porosity, density and thermophysical properties alter heat transfer during roasting, and different roast profiles materially change acidity dynamics. So for these two coffees, 230°C is only the starting point. The result is decided by how we pace energy after charge, African Moon gets a profile that protects bright fruit structure; Brazilian Eagle gets a profile that deepens body and chocolate sweetness.
Natural vs Washed: Processing Differences That Actually Matter
If you want a clean benchmark, compare this with our washed process guide. Naturals and washed coffees are not just different styles; they are different risk profiles and processing systems.
| Feature | Natural Process | Washed Process |
|---|---|---|
| Drying | Dried inside the whole fruit | Dried in parchment after fruit removal |
| Flavour tendency | Jammy fruit, funk, heavier body | Cleaner, floral/citrus, more transparent acidity |
| Processing risk | Higher mould/over-fermentation risk | More controlled and consistent when managed well |
| Water demand | Very low process-water demand | Higher water demand plus wastewater treatment requirement |
The water point is not just theory: reviews of coffee wastewater management show wet processing can create high-organic-load effluent that needs treatment, which is why water system quality is central in washed lots (critical review in Cleaner Engineering and Technology; field evidence from Ethiopia).
Cupping naturals side-by-side is the fastest way to feel how processing changes body, fruit, and finish.
The Solubility Factor: Why Your Brew Recipe Should Change
In our own brews, naturals often extract quickly and can tip into fermenty bitterness if pushed too hard. Start with a slightly coarser grind than your washed recipe and lower your brew water a touch.
Brewing Tip
For V60 naturals, start around 90-92°C and grind one step coarser than your washed baseline. If you are brewing Brazilian Eagle, this usually keeps sweetness high and ferment notes clean. For method details, use our V60 guide.
Naturals usually reward a gentler brew setup: slightly cooler water and a cleaner extraction path.
Natural Is Not One Thing: Origin Changes Everything
“Natural” is a process category, not a single flavour. Country and climate still dominate the outcome:
- Ethiopia naturals: often blueberry/jasmine intensity
- Brazil naturals: more cocoa, nuts, dried-fruit sweetness, creamy body
- Costa Rica naturals (including Perla Negra styles): can show winey acidity with cleaner structure
That is why we always cup naturals as origin + process together, never process name alone.
Common Pitfalls: When Natural Processing Goes Wrong
Natural coffees are high-reward, high-risk coffees. The same long drying window that builds complexity also increases defect risk if conditions drift. The speciality processing quality review points out exactly this trade-off: natural processing can produce exceptional cups, but quality control demands are higher.
Typical faults include over-fermented vinegar notes, muddy cups, mould taint, and uneven sweetness. Our QC response is simple: reject lots that are loud but dirty, and keep only naturals that are expressive and clean.
The Verdict: Is Natural Coffee Right for You?
Choose natural process coffee if you enjoy fruit-forward flavour, a heavier body, and a bit more wildness in the cup. Choose washed coffees if you want tea-like clarity and tighter acidity structure.
You can read all about coffee processes and how we roast them on our Ultimate Coffee Processing Guide
For a refined high-altitude natural profile, start with African Moon. For a chocolate-led natural that works beautifully on espresso, start with Brazilian Eagle.
Curious? Grab a bag of African Moon here and taste what clean, natural processing can do.
