Origin gets the attention on a bag of coffee, and processing gets a single word in smaller type. For predicting what the coffee will actually taste like, the small word is often doing more work than the country name above it.
Processing is what happens to the coffee cherry in the days after picking, and it is the single biggest lever on flavour after the coffee reaches the mill. Washed tastes cleaner and more acidic. Natural tastes fruitier, heavier and less predictable. Honey sits between them. That is the whole answer, and everything below is why.
The fruit is the point
Coffee grows as a cherry. Inside the fruit are usually two seeds, and those seeds are what gets roasted. Between picking and drying, someone has to decide how to get the fruit off, and how long the seed spends in contact with it on the way.
Sugar migrates. The longer the seed sits against sweet, fermenting fruit, the more of that character ends up in the finished coffee. Processing is essentially a decision about how much fruit contact to allow, and how carefully to control the fermentation that happens during it.
Washed
The fruit is removed mechanically soon after picking, then the sticky mucilage still clinging to the seed is broken down, usually by a controlled soak, and washed off. The bean is dried more or less bare.
The result is a cup where the origin and the variety are exposed. Washed coffees are typically brighter, more acidic, cleaner, and more consistent from bag to bag. If you want to taste what a particular farm or altitude does, washed is the honest window.
It is also the most water-intensive and the most infrastructure-dependent of the three, which matters for where it is common.
Natural
The whole cherry is dried intact, fruit and all, often on raised beds, and the dried fruit is stripped off at the end. The seed spends weeks against fermenting sugar.
Natural coffees taste of that. Expect heavier body, lower perceived acidity, and pronounced fruit: berry and stone fruit most often, sometimes tipping into something closer to wine or fermented fruit. When it is done well it is the most immediately delicious coffee many people ever drink. When it is done badly it tastes of rot, and the gap between those two outcomes is wider than in any other method, because uncontrolled fermentation is unforgiving.
Ethiopia and Brazil are the two origins most associated with it, for different reasons: one for climate and tradition, the other for scale and sunshine.
Honey
A middle path. The skin is removed but some or all of the sticky mucilage is left on during drying. The mucilage is not honey and there is no honey involved. The name comes from how the drying beans look and feel.
Producers often grade it by how much mucilage was left: white, yellow, red and black honey, in roughly ascending order of fruit contact and therefore of sweetness and body. A black honey is closer to a natural. A white honey is closer to a washed.
Honey processing is labour-intensive and needs close attention during drying, which is part of why it commands a premium.
What processing will not tell you
It will not tell you whether the coffee is good. A carelessly processed washed coffee from a great farm will beat a carelessly processed natural, and vice versa. Processing predicts a flavour direction, not a quality level, and reading it as a quality ladder is the most common mistake.
It also will not tell you how it was roasted, and roasting can flatten the differences considerably. A very dark roast makes washed, natural and honey converge, because at that point you are largely tasting the roast. The distinction is most legible in lighter roasts, which is where specialty roasters spend most of their time.
And it says nothing about ethics or about what the farmer was paid. Natural processing uses less water, which is genuinely relevant in dry regions. That is an environmental fact, not a fair-trade one, and the two get conflated constantly.
The honest recommendation
If you do not know what you like, buy one washed and one natural from the same origin, roasted by the same roaster, and drink them in the same week. That single comparison teaches more than any amount of reading, including this.
Then buy for the direction you liked, not for the origin. Someone who loves natural Ethiopians will usually enjoy a natural from somewhere else far more than a washed from Ethiopia. Processing travels better as a preference than country does.
We do not sell coffee, so we have nothing riding on which you pick. What we would say is that this is the label worth learning, and the one most likely to make your next bag a better guess than your last one.