Washed vs. natural processing
The two oldest processing methods: what each does to the fruit, what each costs in water and drying, and how the trade describes the result.
In short
A coffee bean is the seed of a fruit. Processing is how the fruit is taken off and the seed dried. In the washed process the skin and pulp are removed first and the seed dries on its own. In the natural process the whole fruit is dried with the seed inside and removed afterwards.
The trade describes washed coffees as cleaner and brighter and naturals as fruitier, sweeter and heavier. That is what buyers expect. CoffeeHQ has read no study that tasted the two made from the same fruit, so the word on the bag is a hint about the cup, not a promise.
Where the two routes part
Widely documented
Harvest and sort
Both begin the same way: ripe cherries are picked and the unripe, overripe and damaged ones removed.
Washed: pulp, ferment and wash
The skin and most of the flesh are stripped off mechanically. The sticky layer left on the seed is loosened by fermentation, usually in tanks, and then rinsed away.
Natural: straight to drying
Nothing is removed. The intact cherries go directly onto patios or raised beds.
Dry
Washed seeds dry in their papery inner husk. Whole cherries have almost twice as much water to lose for the same green coffee, on the Food and Agriculture Organization's figure, and must be turned often: a layer left unturned has been seen to become covered in mould.
Hull
Once dry, the husk, and for naturals the whole dried fruit, is milled off to leave the green bean.
An outline of the two routes. Practice varies by country and by mill, and honey or pulped natural processing sits between them by leaving some fruit on the seed.
What drying in the fruit might change
CoffeeHQ explanation
In a natural, the seed dries surrounded by sugary, fermenting fruit. The authors of one large trial of wet processing read their measurements as showing the seed's own metabolism still active through processing, so the conditions around it plausibly matter. The trade's account of the outcome is more fruit-like sweetness, a heavier body and lower perceived acidity. No document read for this page tested that against a washed coffee from the same fruit.
A washed coffee has the fruit removed within hours. What is left is often described as a clearer view of the coffee itself: the variety and the place it was grown. That is a way of speaking, and washed coffee is not one thing: in the same trial, the same cherries gave detectably different cups depending on how long they were fermented. How much of any difference is down to fermentation as opposed to the seed's own biology, the trials read do not settle.
Risk, water and why regions choose as they do
Widely documented
Washing needs a reliable supply of clean water and produces wastewater that has to be managed. Natural processing needs neither, but it needs dependable dry weather and a great deal of labour to turn the fruit. The FAO guidance says drying in the cherry can give safe, good coffee where the harvest season is reliably arid, and notes that most robusta is dried this way and most arabica washed, with important regional exceptions. Brazil and Ethiopia both dry much of their arabica in the cherry.
The risk profile differs too. A natural that dries too slowly gives mould time to grow, and cherries held in heaps before drying ferment in a way the guidance calls uncontrolled. The same guidance notes that parchment coffee has a higher market value and costs more to produce, and that drying cherries well takes as much management as the more complicated wet process.
How far to trust the label
Tendency, not a guarantee
- A good guide to
- What the trade expects of it. A natural is sold as heavier and more fruit-forward, a washed coffee as lighter and crisper, and roasters choose and describe coffees accordingly.
- A poor guide to
- Quality. Both methods produce outstanding and dreadful coffee. A clean, careful natural can be more transparent than a carelessly washed lot.
- Outweighed by
- Roast level. A dark roast is commonly said to flatten the differences between processes; nothing read for this page measured it.
The most instructive tasting you can buy
CoffeeHQ explanation
One farm, two processes
- Change
- Some roasters sell the same coffee from the same producer both washed and natural. Buy both and brew them side by side.
- Keep the same
- The brew method, ratio, grind and water. Ideally a similar roast level too.
- What to notice
- With origin and variety held the same, what differs between the cups is as close as you can get at home to tasting processing on its own. It is still two lots, picked and dried separately, and tasting them before reading the bags keeps the label from deciding for you.
What to do next
- The washed process — Each stage in more detail, including fermentation.
- The natural process — Drying, the risks involved and where it is traditional.
- Honey process — The method that sits between the two.
- How to compare two coffees — A simple way to set up the side-by-side tasting suggested above.
At a glance
| Aspect | Washed (wet) process | Natural (dry) process |
|---|---|---|
| Cherry handling | Skin and pulp removed before drying; mucilage fermented off | Whole cherry dried intact around the bean |
| Water use | Higher — depulping and washing require water | Lower — drying does not require washing water |
| What has to be dried | The seed in its parchment | The whole fruit: almost twice as much water to remove for the same green coffee, on the FAO guidance's figure |
| How the trade describes the cup | Cleaner and brighter. A description of what buyers expect, not a finding | Fruitier and heavier. Likewise an expectation, not a finding |