Specialty Coffee Wiki

Washed process

Properties3
descriptionThe method that strips every scrap of fruit off the coffee seed before it is dried, so what you taste is the seed and the place rather than the fruit. It is the default for specialty coffee almost everywhere except Brazil, and it costs water.
tagsconcept, processing, fermentation
aliasesWashed processing, Washed coffee, Washed process coffee, Wet process, Wet processing, Wet method, Fully washed, Fully washed coffee, Double washed, West Indies Process, methods-and-concepts/washed-process, concepts/washed-process

19 min read

Washed process

Washed process — also called wet process — means all the fruit comes off the coffee seed before it is dried. The skin is squeezed off by machine, the sticky sugary layer underneath is broken down and rinsed away, and only then does the bare seed, still wrapped in its papery parchment shell, go out to dry.1

Carlos Oliveros, Principal Investigator at Cenicafé — the research centre of Colombia’s national coffee federation — gives the definition in one line: “A washed coffee is a coffee which has had various fruit layers removed before drying begins. We have removed the skin, we have removed the mucilage”.2 Counter Culture Coffee describes the same rule from the practical end: “the fruit is removed from the seed as soon as possible after picking, before the drying process begins”.3

Mucilage is the word that does all the work here. It is the thin, slippery, sugar-rich layer glued to the seed once the skin is off — the same layer honey process deliberately leaves on and natural process never removes at all. Washed processing exists to get rid of it.

That one decision — fruit off first, dry a bare seed — is the whole method. Everything else follows.

”Wet process” and “washed process” are not quite the same word

The two names are used interchangeably across the trade, and for nearly every practical purpose that is fine. But there is a distinction underneath them: wet process describes broadly using water during post-harvest preparation, while washed process points specifically at removing the mucilage by fermenting it and rinsing it away.4 “Washed” has become the preferred modern term precisely because it names the defining step rather than the medium it happens in.4

In practice the two labels land on the same coffees: almost anything depulped by machine, fermented until the mucilage lets go, and thoroughly rinsed before drying gets called washed.4

To verify

Whether the tank holds water does not change the label. One coffee-education source states that fermentation tanks may be run either dry or with water added, and that both still count as washed or wet-processed so long as the mucilage comes off and the coffee is rinsed clean.5 That is consistent with Coffee fermentation, which notes the ferment “is sometimes done underwater,” but the page could not be retrieved to confirm the wording, and no second source consulted here says it explicitly. Treat the dry-versus-underwater tank as a variation within washed processing, not as a separate method — but check a wet-mill manual before quoting it as a rule.

How it actually happens

  1. Float and sort. Cherries are tipped into water. Ripe fruit sinks; underripe, overripe and insect-damaged cherries float and are skimmed off.6
  2. Depulp, fast. The fruit goes through a depulper — “machines that squeeze the fruit between rollers until the seeds pop out”. This happens within 24 hours of harvest.78 Oliveros adds a detail most guides skip: the coffee should be passed through a sieve afterwards, because some cherries come out of the depulper only half-stripped.
  3. Ferment. The depulped seeds go into tanks. “Through fermentation, microbes and yeast are used to break down the mucilage”. The microbes are not added — they are already on the fruit — and time, temperature and acidity all steer what they produce.
  4. Wash. Once the mucilage has broken down, the coffee is rinsed with clean water, often in channels, until the parchment squeaks clean.
  5. Dry. The parchment-covered seed goes onto patios, raised beds or into mechanical dryers until it is dry enough to store safely.
  6. Rest, then mill. Dried parchment coffee is stored, then dry-milled — the parchment and the thin silverskin under it are stripped off — and the green coffee is graded, sorted and bagged for export.

Steps 3 and 4 are what people mean by “washed.” Steps 1, 2, 5 and 6 happen in some form to almost every coffee.

One thing the word does not mean. “Washed” describes rinsing sugar off a seed during processing — it is not a claim about hygiene, and a washed coffee is not more hygienic than a properly processed and dried natural one.9 The word describes a step, not a grade.

The numbers, and where they disagree

Four sources give timings for the same process and they do not line up. That is not sloppiness — it is the honest state of the practice.

StageWhat the sources say
DepulpingWithin 24 hours of harvest
Fermentation24–36 hours · 18–24 hours · 12–72 hours · 8–72 hours · “an average of one or two days”
Sun-drying8–10 days · 7–15 days on patios, raised beds or parabolic dryers
Mechanical drying18–36 hours
Final moisturemaximum 12.5% · below 11%, the point at which microbes can no longer work

The wide fermentation spread has a cause. Sprudge puts it bluntly: “there is no one single ‘washed process’—it is a catch-all term used to describe a coffee processing method with many unique sets of decisions”. A tank at 1,800 m in the cold at night behaves nothing like a tank at 600 m in the tropics. Gloria Inés Puerta, Quality Investigator at Cenicafé, ties the Colombian figure directly to conditions — “18 to 24 hours, depending on the temperature and coffee value”.

There is also a subtler point buried in the Cafe Imports figure. Fermentation does not politely stop when the tank is drained: it “may occur from the moment of harvest until the seeds reach an inhospitable moisture content for them (11% moisture)”. The tank time is the managed part of a fermentation that runs, at some rate, right through drying.

The finish line is the same as every other method. ISIC gives a maximum moisture content of 12.5% before storage for washed and natural alike1011 — the target that keeps coffee from moulding in a shipping container. What differs is how long it takes to get there: a bare parchment seed is dry in 8 to 10 days, where a whole cherry lying in the sun takes two to six weeks (see Natural process).

Fermentation is not the only way to get the mucilage off

Some mills skip the tank. A mechanical demucilager scrubs the mucilage off by friction instead — Counter Culture describes “a machine-assisted process to scrub most of the mucilage from the seed through friction”. The coffee is still washed process, because the fruit still comes off before drying. It just gets there by machine rather than by microbes.

Cenicafé has built these machines partly to attack the method’s water problem. Perfect Daily Grind records two: the Becolsub, which removes mucilage in under 40 seconds, and the Ecomill, which cuts water use from 40 litres per kilo to 0.3–0.5 litres per kilo.

That 40-litre baseline is the honest cost of traditional washing, and it matters more than it sounds — see below.

What it costs: water

This is washed processing’s real liability and the reason it is not universal.

Barista Magazine says the method requires an “enormous amount of water,” making it unsuitable for drier regions. Sprudge agrees that washed coffee “does require more water and power resources to produce than natural process coffee,” and notes it is “not as common a method in areas where access to water or the resources to build proper washing stations or wet mills are limited”. Perfect Daily Grind identifies the sharper end of the problem: it is not only how much water goes in, but that improperly disposed wastewater can contaminate local waterways.

To verify

How much water, exactly, is genuinely unsettled. This note and Cenicafé both give a traditional baseline of about 40 litres per kilogram, sourced to Perfect Daily Grind reporting Cenicafé’s own figures.2 A separate processing guide puts washed processing at 15–20 litres per kilogram, confirmed via WebFetch.12 That is a two-to-threefold disagreement about the central environmental fact of the method. The two are not necessarily contradictory — a figure can count only the water that touches the coffee or all the water a mill draws, and recirculating mills use far less than open-channel ones — but neither source states its boundary. The Cenicafé-derived 40 L/kg is the better-provenanced number and is what the Cenicafé note’s 99%-reduction claim rests on; the 15–20 L/kg figure comes from a commercial guide with no methodology given. Take any single litres-per-kilo number as an order of magnitude, not a measurement.

The capital cost compounds it. A washed coffee needs a wet mill — a depulper, tanks, channels, drying infrastructure, and a clean water supply to run through all of it. A natural needs a flat surface and sunshine. That single fact explains most of the world map below, and it is why Robusta, the volume crop, is almost never washed.

Where it sits between the other methods

MethodWhat happens to the fruitTypical result
WashedSkin and sticky mucilage removed before dryingClean, bright, higher acidity, lighter body
HoneySkin off, mucilage left on during dryingSweeter, fuller body, moderate fruit
NaturalWhole cherry dried with fruit intactHeaviest fruit, jammy, lowest acidity, most divisive

Read it as a dial, not three boxes: the more fruit touching the seed while it dries, the more fruit and body in the cup and the less clarity. Washed sits at the far clean end.

One thing the table cannot show: anaerobic is not a fourth column. Sealing the tank is something you do to a washed, honey or natural coffee — “anaerobic washed” is a washed coffee whose ferment happened with the air shut out. See Anaerobic fermentation.

Why it tastes the way it does

Strip the fruit off early and the fermentation has far less sugar to work with and far less time to push flavour into the seed. What is left in the cup is mostly what the plant and the place put there.

The descriptions are consistent across sources:

  • Cafe Imports: “clean, articulate flavors; caramel or sugary sweetness; a wide spectrum of fruit acidity depending on other factors; capable of bright, crisp notes”.
  • Counter Culture: washed coffees “have flavors more inherent to the seed itself… higher acidity, with brighter fruit flavors, lighter body, and classic nutty flavors”.
  • Sprudge: “sparkling acidity, clarity of cup, and brighter fruity notes”.
  • Barista Magazine: “complex flavors, with higher acidity and a more pronounced brightness,” plus a “light body”.

The specialty trade’s actual argument for washed coffee is not “it tastes better.” It is transparency. Oliveros’ colleagues frame it as letting a taster experience “the origin, the coffee variety, the terroir – and not the impact of the processing method,”9 and Perfect Daily Grind adds the commercial reason underneath: washed lots are more consistent than naturals and honeys. Sprudge reaches the same conclusion from the drinker’s side — many prefer washed for “a more pure expression of a coffee’s terroir and varietal typicity”.

To verify

“Cleaner” is a description; “better” is an opinion. Every source above is a roaster, importer or trade publication describing a widely held preference, not a measured result. There is no study consulted here showing washed coffee scores higher, and the top of the auction market flatly contradicts the idea — naturals have set most of the Best of Panama price records of the last decade. Treat “clean and transparent” as an accurate description of what the method does, and treat any claim that it is superior as taste, not evidence.

Where in the world it is the default

Cafe Imports gives the map: washed is “the primary method for preparing specialty-quality coffee in most of Africa, Central and South America (with the exception of Brazil, where it’s uncommon), and select parts of the Asia-Pacific growing region”. Sprudge goes further and calls it “the world’s leading method of preparing coffee for roasting and consumption”.

Nordic Approach, a Norwegian green-coffee importer, draws the same map from the buying side and adds names to it: Ethiopia, Kenya and Colombia are “perhaps the most globally recognised” washed origins, and the majority of coffee from Central America, Peru and East Africa is washed.13

Three independent trade sources agree on the pattern, so the shape is reliable. The exceptions are where the argument lives:

  • Brazil, the largest producer on earth, mostly does not wash — its Arabica is largely natural or pulped natural, because the dry season lines up with harvest and the water bill does not. See Cerrado Mineiro.
  • Ethiopia runs both at scale. Daye Bensa alone operates 16 washing stations in Sidama; Alo Coffee’s Echoes of the Peak auction sells its lots in four processing families, of which washed is one column of four.
  • Kenya built an entire national style on it — see below.
  • Robusta is almost never washed anywhere. Wet mills are capital the Robusta trade has never had reason to spend.

A washing station — also called a wet mill — is the shared facility where smallholders deliver cherry to be pulped, fermented, washed and dried. In origins built on small farms, the station rather than the farm is the real unit of quality: Sucafina owns 60 of them precisely so it controls that step, and Daye Bensa’s 16 stations are what turn tens of thousands of scattered smallholdings into separable lots.

To verify

Kenya’s double washing. This wiki’s SL28 and SL34 notes both state that Kenyan coffee is conventionally double-washed — fermented, rinsed, then soaked again in clean water before drying — and describe the soak as largely specific to Kenya. None of the five washed-process sources fetched for this note mentions Kenya, double washing or the second soak at all: Barista Magazine’s washed-process article describes a single fermentation of “an average of one or two days” and stops there. The claim is not contradicted, merely uncorroborated here. Before quoting the Kenyan soak as fact, check a Kenyan primary source (Coffee Research Institute or the Coffee Directorate) rather than this note.

Where it came from

Washed processing is not African and not Ethiopian. On the evidence of the surviving written record, it is Caribbean.

The oldest name for it says so. In the nineteenth-century coffee literature the method was not called “washed” or “wet” at all — it was the West Indies Process, abbreviated WIP, a label still in use as late as Walsh’s 1894 handbook.14 The name is a small historical joke on itself: Europeans called the Caribbean the West Indies because they thought they had reached India, and the process named after that mistake has nothing to do with either India or the parts of Africa where washed coffee is now the house style.

The archive trail runs like this:14

WhenWhat happened
11723De Clieux, a French officer from Normandy, carries the first coffee plant to Martinique — coffee arrives in the Caribbean
21789Laborie writes the first account in English of wet processing, describing it in Saint-Domingue (now Haiti), then the source of over half the world’s coffee
31830sRobert Boyd Tytler carries the practice to Ceylon (Sri Lanka), and from there it spreads east

So the method is roughly three centuries old, born in the plantation coffee of the New World rather than in coffee’s homeland — which fits the physical logic. Natural is the older method everywhere, and washing only becomes possible once someone has built machinery to strip skin off wet fruit and has water to spare. The Caribbean had both.

To verify

Why it appeared, and the exact chain. The dates above come from a single coffee-science archive site reading eighteenth- and nineteenth-century texts, confirmed by fetching that page but not by consulting Walsh (1894) or Laborie (1789) directly.14 Its central explanation — that Caribbean planters adapted wet processing from the cacao fermentation they were already doing on the same islands — is offered by that author as a theory, not a documented fact, and no second source consulted here corroborates it. The 1723 and 1830s dates are ordinary plantation history and low-risk; the causal story is not. Treat the cacao link as a plausible hypothesis until someone checks the primary sources.

Why it matters

Washed process is where the specialty market’s idea of quality was defined — and, in 2025, where its price ceiling was set.

  • The world record is a washed coffee. Hacienda La Esmeralda’s Washed Geisha, scored 98/100, sold at roughly 13,705/lb** at the 2025 [[Best of Panama]] auction — about **604,000 for a single 20 kg bag, after 549 bids, to Julith Coffee of Dubai.15 It was also the first BoP lot in history to draw perfect 100-point scores from judges. See Best of Panama results archive.
  • It is a competition category, not just a technique. Best of Panama splits entries into Geisha Washed, Geisha Natural and Varietals. Washed is a column on the scoresheet, which means farms deliberately prepare separate washed and natural lots from the same trees — the cleanest demonstration anywhere that processing, not just the plant, decides the cup. Finca Sophia won the washed Geisha category in 2017 and 2020.
  • Whole varieties are built around it. Kenya’s SL28 and SL34 are grown, milled and traded as washed coffees; the blackcurrant acidity they are famous for is a washed-process signature. Sey Coffee’s light-roast style exists to expose exactly that.
  • It is the baseline everything else is measured against. When anaerobic, honey and experimental lots are described as “fruity” or “intense,” washed is the implicit comparison. Jean Paul Langenstein at Carmen Estate runs hot-and-cold fermentation regimes on washed Geisha — the experiment is on top of the washed template, not instead of it.

For a reader, the practical shortcut: “washed” on a bag is a promise of clarity and brightness, not of fruit — and it tells you the farm had access to water, machinery and a mill, which is itself information about the coffee.

Footnotes

  1. The Coffee Bean & Tea Leaf — Processing 101: What is Washed Coffee? — cited in the research report, not independently fetched ↩

  2. Perfect Daily Grind — Processing 101: What Is Washed Coffee & Why Is It So Popular? (December 2018) — source of the Cenicafé definitions (Carlos Oliveros, Gloria Inés Puerta) and the Becolsub/Ecomill water figures; confirmed via WebFetch ↩ ↩2

  3. Counter Culture Coffee — Coffee Basics: Processing — depulpers, fermentation, washing, demucilaging and flavour profile confirmed via WebFetch ↩

  4. Roastopedia — Washed Process (Wet Process) — coffee reference site; the wet-process / washed-process terminology distinction and the “oldest and most influential post-harvest method” framing confirmed via WebFetch. The page cites World Coffee Research, the International Coffee Organization, the Specialty Coffee Association, the Coffee Quality Institute and the Illy & Viani / Clarke & Macrae / Wintgens technical literature as its own sources, but gives no water-use figures ↩ ↩2 ↩3

  5. Nordic Brew Lab — Washed Coffee Processing, Explained — cited in the research report as the source of the with-or-without-added-water tank claim; the page returned an HTTP 429 and could not be independently fetched ↩

  6. Sprudge — What Is “Washed” Process Coffee? — “world’s leading method,” the “no one single washed process” caveat, and the water/power criticism confirmed via WebFetch ↩

  7. Cafe Imports — Washed Process — green coffee importer; fermentation range, drying times, 11% moisture threshold and regional prevalence confirmed via WebFetch ↩

  8. Barista Magazine — Understanding the Process, Part Two: Washed/Wet (Tanya Nanetti, 29 August 2022) — 24-hour depulping window, fermentation duration, water use and flavour profile confirmed via WebFetch ↩

  9. Cocondo Coffee — What Is Washed Coffee? The Process Behind Clean, Bright Cups — cited in the research report as the source of the “terroir-transparent” phrasing and the clarification that “washed” is not a hygiene claim; a blog, not independently fetched ↩ ↩2

  10. ISIC (institute for scientific information on coffee) — Initial coffee bean processing — industry scientific body; wet-method steps, 24–36 hour mucilage removal, 8–10 day sun-drying and the 12.5% moisture ceiling all confirmed via WebFetch ↩

  11. Specialty Coffee Association — Coffee Standards ↩

  12. Brewed Barista — Coffee Processing Methods: Washed, Natural & Honey Explained — commercial guide; the 15–20 litres-per-kilogram water figure, the 12–72 hour fermentation range and the “clean, bright acidity and clear origin character” description confirmed via WebFetch. No methodology given for the water figure ↩

  13. Nordic Approach — What is Washed Process Coffee? — green-coffee importer; the named washed origins and the Central America / Peru / East Africa prevalence confirmed via WebFetch ↩

  14. Curious About Coffee Science (Dr. Kôfē) — Washed Coffee History — the “West Indies Process” (WIP) terminology attributed to Walsh (1894), Laborie’s 1789 Saint-Domingue account, de Clieux’s 1723 Martinique planting and Tytler’s 1830s transfer to Ceylon, all confirmed via WebFetch; the cacao-adaptation explanation is the author’s own hypothesis ↩ ↩2 ↩3

  15. Best of Panama — official competition site — 2025 washed Geisha record and category structure, as recorded on Best of Panama and Best of Panama results archive ↩

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