Processing
Coffee Processing Methods
What happens between the cherry and the green bean is the largest single lever on the cup available at origin — and the one a buyer can specify most directly. This is how each method works, and where each one goes wrong.
The chain
From cherry to export preparation
Every method shares the same skeleton. What differs is when the fruit is removed and how much of it stays in contact with the seed during drying.
- Cherry reception, floatation and sorting
- Pulping — skin and pulp removed
- Fermentation, 12–36 hours
- Washing and channel grading
- Optional clean-water soak
- Drying in parchment to target moisture
- Rest in parchment
- Hulling, screening and sorting
Compared
The methods side by side
Read down the columns to choose a preparation; read across the rows to see what changes when you do.
| Method | What happens | Cup tendency | Where the risk sits | Typical origins |
|---|---|---|---|---|
| Washed | Cherry is pulped, the remaining mucilage is removed by fermentation and washing, and the parchment is dried. The cup reflects the seed and the terroir more than the fruit. | Cleaner, more transparent acidity and a lighter body than the same cherry processed dry. Origin and variety character reads more clearly; defects also read more clearly. | Requires reliable water, effluent management and disciplined fermentation control. Over-fermentation produces sour and phenolic cups; under-fermentation leaves mucilage that stains parchment and slows drying. | The default for Kenya, Rwanda, Burundi and Tanzanian Arabica; a large share of Ethiopian Yirgacheffe and Sidama; the WUGAR designation in Uganda. |
| Natural | Whole cherry is dried intact, then hulled. The fruit stays in contact with the seed throughout drying, which is what drives the characteristic sweetness and body. | Heavier body, lower perceived acidity, pronounced fruit sweetness — berry and tropical notes in Ethiopian lots, dried fruit and spice in Ugandan DRUGAR. | The highest-risk process to execute. Uneven drying produces mould, ferment and phenolic taints; the defect is invisible in the green and only shows in the cup. Requires space, labour and settled weather. | The default for Ugandan Robusta and Ethiopian Harrar and Djimma; a substantial and growing share of Ethiopian Sidama and Guji; increasing volumes in southern Tanzania. |
| Honey | Cherry is pulped but the mucilage is left on the parchment during drying, in a controlled fraction. Sits between washed and natural in both process and cup. | More sweetness and body than washed, more clarity and structure than natural. Acidity is usually rounded rather than sharp. | The sticky parchment is prone to clumping and surface mould in the first two days. Requires bed space and labour comparable to naturals with the sorting discipline of washed. | Produced in limited volumes across Rwanda, Burundi, Tanzania and Ethiopia. Availability is small and lot-specific, so it should be confirmed rather than assumed. |
| Semi-washed | Parchment is removed at an elevated moisture content partway through drying. Rare in East Africa but occasionally encountered in Rwandan "ordinary" preparations. | Heavier body, lower acidity, earthy and herbal notes. The green appearance is characteristically dull and bluish. | Hulling at high moisture bruises the seed and creates entry points for mould. Not used for specialty separations in this region. | Mainly associated with Indonesia. In East Africa it appears occasionally in lower-grade Rwandan and Burundian parcels. |
Unit operations
What each method actually does
The step lists below are the mill's view rather than the marketing one. They are also where the cost and the labour sit.
Fully washed (wet processed)
Read more about Washed processing- 01Cherry reception, floatation and hand sorting to remove unders, over-ripes and foreign matter
- 02Pulping to strip the skin and most of the pulp from the seed
- 03Fermentation in tanks — typically 12–36 hours depending on altitude and ambient temperature
- 04Washing and grading in channels, which also separates by density
- 05Optional soak (standard in Kenya, common in Burundi) in clean water for a further 12–24 hours
- 06Drying on raised beds or patios in parchment to the target moisture
- 07Rest in parchment, then hulling, screening, density and colour sorting at the dry mill
Natural (dry processed)
Read more about Natural processing- 01Cherry reception, floatation and sorting — more critical here than in washed processing, since nothing later removes an under-ripe
- 02Spreading whole cherry in thin layers on raised beds or patios
- 03Frequent turning, with early-stage layers kept thin to avoid mould and internal fermentation
- 04Shading or covering during peak sun and overnight to control the drying rate
- 05Drying over roughly two to four weeks depending on climate and layer depth
- 06Rest in cherry, then hulling to remove dried skin, pulp and parchment in one operation
- 07Screening, density and colour sorting at the dry mill
Honey / pulped natural
Read more about Honey processing- 01Cherry reception, floatation and sorting
- 02Pulping without a fermentation or washing step
- 03Optional partial mucilage removal — the fraction left on determines the yellow / red / black designation
- 04Drying in mucilage-coated parchment on raised beds, with very frequent turning in the first 48 hours
- 05Slower, more closely managed drying than washed parchment
- 06Rest, hulling and dry-mill sorting as for washed
Semi-washed / wet-hulled
Read more about Semi-washed processing- 01Pulping and short fermentation
- 02Partial drying in parchment
- 03Hulling while the seed is still well above final moisture
- 04Completing the drying on the exposed green bean
Specifying
Writing the process into a contract
- Name the preparation exactly. “Fully washed” and “fully washed with soak” are different processes with different cups. Kenya and Burundi soak as standard; most other origins do not.
- Do not infer process from origin. Ethiopia, Tanzania and Uganda all produce both washed and natural at scale. An unspecified Ethiopian lot is not a specification.
- For naturals, cup more cups. Drying faults are intermittent across a lot and invisible in the green. A three-cup sample can miss what a five-cup sample finds.
- Tie it to the approved sample. The process name sets the expectation; the retained sample is what the delivery is measured against.
What we do not claim
We describe how these processes work at origin generally. We do not claim to own or operate washing stations, mills or drying facilities, and photographs on this site are not documented as depicting the origins we supply.
Questions
Processing questions buyers ask
Which processing method produces better coffee?
Neither. They produce different coffee. Washed processing shows the seed and the terroir more transparently; natural processing adds fruit sweetness and body. A well-executed natural beats a poorly executed washed and vice versa. Execution quality varies far more than method does.
Can I specify the processing method in a contract?
Yes, and you should — it is one of the few origin-side variables a buyer can specify directly. State it explicitly ("fully washed", "fully washed with soak", "natural") rather than leaving it implied by the origin, because several origins produce more than one preparation.
Why is natural processing described as higher risk?
Because the fruit stays on the seed for two to four weeks of drying, and anything that goes wrong in that window — layers too deep, insufficient turning, rain — produces mould, over-fermentation or phenolic taint. Crucially the damage is invisible in the green coffee and only appears in the cup, so it survives visual inspection.
Is honey process available from East Africa?
In limited volumes from Rwanda, Burundi, Tanzania and Ethiopia. It is lot-specific rather than a standing offer, so availability should be confirmed for the crop in question rather than assumed.
Does processing matter more than origin?
They interact. Processing is the single largest lever on the cup available at origin, but it acts on what the cherry brings — altitude, variety, ripeness at picking. A natural process cannot add sweetness that under-ripe cherry never had.