The oldest method in coffee
Natural processing is exactly what the name suggests: the fruit is left alone. After harvest, whole ripe cherries go straight onto drying beds with the skin, pulp, and mucilage still intact. Nothing is removed until the coffee is dry. Then the dried fruit is hulled off mechanically to reveal the green bean underneath.
That's it. No washing stations, no depulping machines, no fermentation tanks. The process existed before any of that infrastructure did.
It developed where it had to. Ethiopia and Yemen, the two places where coffee cultivation began, have dry climates, strong sun, and historically limited access to water. Laying out the whole cherry to dry was the practical answer. It remains the dominant method in parts of Ethiopia today, and is widely used in Brazil, Yemen, and Costa Rica.
Coffee science generally sorts processing into three broad categories, distinguished by how much fruit stays on the bean and how oxygen and water are managed during fermentation: dry processing (natural), semidry (honey), and wet processing (washed). Natural sits at one end of that spectrum. The whole cherry stays in place from harvest to hulling, and any fermentation that happens does so in open air, with no water added at all.
Where natural process coffee is grown
Coffea arabica originated in Ethiopia's highland forests, and it was Yemeni traders who first carried the plant across the Red Sea and began cultivating it as a crop. Both countries still hold hundreds of traditional arabica varieties found nowhere else, and both still dry a large share of their coffee as whole cherry, largely for the same reason: reliable water for washing has historically been scarce across much of both countries.
In Ethiopia, natural processing remains the standard in Harrar, in the country's east, where nearly all coffee is still dried as whole fruit. Natural lots also make up a meaningful share of production in Yirgacheffe, Sidama, and Guji, in the south, even though those same zones are equally well known for washed coffee. It's common for a single washing station in these regions to produce both washed and natural lots from cherry grown on the same slopes, sorting fruit by quality and intended drying method rather than by farm.
In Yemen, coffee still grows on ancient hand-built stone terraces climbing the mountains of regions like Haraaz and Bani Matar, between roughly 1,500 and 2,500 metres above sea level. Each terrace doubles as a small reservoir, capturing seasonal rainwater and channelling it down the slope through stone and mud irrigation built by hand over centuries, since there is no other reliable water source at that altitude. Farms are tiny, often under a hectare, worked without synthetic fertiliser or pesticide, and drying the whole cherry in the sun remains the only practical option. It is one of the reasons Yemeni coffee is sold in such small volumes and at such a premium.
Outside East Africa, Brazil is the largest producer of natural process coffee by volume. Its flatter terrain and drier harvest season make mechanised patio and raised-bed drying practical at a scale that's rare elsewhere, and most of the country's natural coffee moves through large estates rather than smallholder cooperatives. Costa Rica also produces natural and semidry lots, driven less by water scarcity than by a specialty market that rewards distinctive, fruit-forward processing.
What happens during drying
The drying stage is where natural processing gets interesting and difficult.
From the moment a cherry is picked, fermentation starts. Yeast and bacteria present in the fruit begin metabolising the sugars and acids inside. Because the whole cherry stays intact, that fermentation happens slowly, inside the fruit, over the full duration of drying: typically 15 to 30 days depending on climate and conditions.
The process continues until the coffee reaches around 10 to 11% moisture, at which point the environment becomes too dry for microorganisms to survive and the beans are stable enough to store and mill without cracking. Unlike washed processing, where fermentation happens in tanks over a defined period, natural fermentation has no hard off switch. The producer manages it indirectly, through how thickly cherries are spread on the beds, how often they're turned, how much sun and airflow they get.
Many specialty producers now dry on raised mesh beds rather than ground-level patios, since air can move underneath the cherry layer as well as over it. That underside airflow makes drying more even across a batch than a solid concrete surface allows, which matters when the difference between a clean lot and an inconsistent one comes down to how uniformly moisture leaves each cherry.
This is what makes natural processing demanding. Uneven drying creates pockets where fermentation continues longer than intended. Too much moisture, from rain, humidity, or cherries piled too deep, raises the risk of mould. Overfermentation produces off-flavours: sharp acetic notes, a vinegary or barnyard quality that signals something went wrong. A good natural requires daily attention and experienced hands throughout the entire drying period.
It also requires space. Cherries need room to dry evenly, which means significant surface area on the drying beds, more than a washed process demands. Natural processing uses far less water, which matters in the regions where it's most common, but the trade-off is in labour, land, and time.
Common defects and how producers manage them
Because fermentation in natural processing has no defined stopping point, the same conditions that build sweetness and fruit character can just as easily tip into fault if left unmanaged.
The most common defect is what producers call a "stinker": an individual bean where fermentation has run too far, producing a rotten, sulphurous, or intensely vinegary note. A handful of stinkers scattered through an otherwise good lot can taint the whole cup, which is why careful hand sorting after hulling matters as much as the drying itself. Mould is the other major risk, usually the result of cherries piled too deep or drying too slowly in humid conditions. Both defects are reasons naturals are sorted more aggressively than washed lots before export.
Good management comes down to attentive, repetitive labour: raking cherries several times a day to redistribute moisture, spreading them thinly enough that air reaches every layer, and moving them under cover during rain. Producers who do this consistently, harvest after harvest, are the ones whose naturals command the higher end of the specialty market. It is also why a well-managed small-lot natural often costs more than a washed coffee from the same farm. The extra labour and risk are priced in.
Innovations in natural processing
Some producers have started taking more direct control over fermentation itself, rather than leaving it entirely to ambient conditions. Anaerobic natural processing seals whole cherries in airtight tanks or fruit-safe plastic drums before drying, sometimes with carbon dioxide added to displace oxygen. Restricting oxygen changes which microorganisms are active and slows certain reactions, giving the producer more control over the fermentation's direction and duration before the cherries ever reach the drying bed.
Recent trials in Colombia comparing CO2-assisted fermentation against a conventional natural process found the CO2-treated lots scoring meaningfully higher on the SCA's 100-point cupping scale, an average of roughly four to five points above the control. Researchers linked this partly to the modified atmosphere preserving more of the cherry's natural sugars and acids through fermentation rather than losing them to unchecked microbial activity. It is one reason anaerobic naturals have become a distinct, often higher-priced category in specialty coffee over the past decade, sitting alongside traditional naturals rather than replacing them.
What you taste
The long contact between bean and fruit leaves a clear mark on the cup.
As the cherry dries, sugars and organic compounds from the fruit gradually migrate into the seed. The result is a coffee that tends to carry more sweetness and more body than its washed counterpart, with a flavour profile that leans toward fruit. Berry notes are common: blueberry, strawberry, raspberry. Stone fruit and dried fruit appear often. Some naturals have a wine-like or jammy quality, a roundness that reads almost as fermented sweetness when the process is done well.
Acidity is usually softer and less defined than in washed coffees. Where a washed coffee might be bright and precise, a natural tends to be fuller and more enveloping. Anaerobic naturals often push this further still, with more pronounced tropical fruit and sometimes a boozy, fermented intensity that traditional sun-dried naturals rarely reach.
That said, natural process coffee is not a single thing. An Ethiopian natural from a high-altitude smallholder farm in Guji will taste nothing like a Brazilian natural processed on a large estate at lower elevation. The fruit contact sets the conditions, but origin, variety, and altitude still determine where those conditions lead. A well-managed natural from exceptional fruit can be one of the most expressive coffees you'll encounter. A poorly managed one, overfermented and inconsistently dried, can be among the most difficult to drink. Our own naturals make that point clearly: a heavy-bodied, chocolate-and-raspberry Red Catuaí from Brazil and a bright, floral heirloom natural from Ethiopia's Guji zone go through the same basic process and land nowhere near each other in the cup.
The process amplifies what's already there. Which is why it rewards good cherry selection and careful drying more than almost any other method.
