Processing is one of the most significant , and least discussed , variables in coffee flavour. The decisions made at the farm immediately after picking shape the sweetness, acidity, body and character of your cup more than almost any other factor. Here is what you need to know.
Quick Summary
- Processing refers to how the coffee cherry is handled after harvesting to extract the green bean
- The five main methods are: washed, natural, honey, anaerobic and wet-hulled (Giling Basah)
- Washed coffees are cleaner and brighter; natural coffees are sweeter and fruitier
- Honey process sits between washed and natural in both technique and cup character
- Anaerobic processing is the most experimental , producing intense, complex, sometimes polarising flavours
- Wet-hulled processing is unique to Indonesia and produces the earthy, full-bodied cups Indonesia is known for
When a coffee is described as "washed," "natural," or "honey processed," these are not marketing terms , they are fundamental descriptions of how the coffee was physically prepared after harvest. Processing affects the flavour in your cup profoundly. Understanding the methods helps you make better purchasing decisions, predict what a coffee will taste like before you brew it, and appreciate why the same origin can produce dramatically different cups across different harvests and producers.
This guide covers all five major processing methods, explains how each one affects flavour, and connects each method to specific coffees in our range so you can taste the difference for yourself.
Why Processing Matters
The Coffee Cherry
Coffee starts as a fruit , the coffee cherry. Inside each cherry are typically two seeds (the coffee beans we roast). The cherry consists of several layers around the seeds: the outer skin, a sugary mucilage layer, a parchment layer, and a thin silver skin directly surrounding the bean.
After harvesting, the farmer must remove these layers to expose the green bean, which can then be dried, sorted, milled and exported. How these layers are removed , and how much of the mucilage remains on the bean during drying , is what processing describes.
Processing and Flavour
The mucilage layer contains sugars and organic acids. During drying, if the mucilage remains in contact with the bean, those sugars and acids are absorbed into the green coffee, fundamentally altering its flavour profile. A naturally dried coffee (where the whole cherry dries around the bean) will taste sweeter, fruitier and heavier-bodied than a washed coffee from the same farm, simply because of how it was processed.
This is why processing knowledge matters: it predicts flavour direction. Once you understand the methods, you can look at a coffee description, see "washed Ethiopian," and anticipate clean, bright citrus and floral notes. See "natural Brazilian" and expect rich dark fruit, chocolate sweetness and full body. The processing method is the first flavour signal you receive before the coffee even touches your grinder.
The Five Main Processing Methods
1. Washed (Wet) Processing
How it works: The coffee cherry skin is mechanically removed immediately after harvesting (pulping). The mucilage is then removed by fermentation , the beans are soaked in water tanks for 12 to 48 hours, allowing the sticky mucilage to break down enzymatically. After fermentation, the beans are washed clean with water and then dried on raised beds or patios until they reach the correct moisture content (approximately 11%).
What it does to flavour: Washed processing removes almost all of the mucilage before drying, so the bean develops without the influence of the fruit sugars. The result is a cleaner, brighter cup that more directly expresses the character of the bean itself , its terroir, variety and altitude , rather than the processing.
Flavour profile: Clean, bright acidity. Floral and citrus notes are common. Higher clarity and transparency in the cup. Less sweetness and body than natural processing. Often described as "clean" or "crisp."
Origin association: Ethiopia (particularly Yirgacheffe), Colombia, Kenya, Guatemala, Rwanda, El Salvador. Washed processing dominates in countries with reliable water supplies and established wet mill infrastructure.
In our range: The Colombian Inza Pedregal is a washed coffee , its clean citrus acidity and clarity are direct products of washed processing. The Guatemalan and Peruvian are also washed, producing the clean chocolate and plum notes they are known for. Our Rwandan is washed , expect sweet, creamy complexity with high clarity.
2. Natural (Dry) Processing
How it works: The whole coffee cherry , skin, mucilage, parchment and all , is dried in the sun without any prior pulping or washing. Cherries are spread on raised drying beds or patios in thin layers and turned regularly to ensure even drying and prevent fermentation becoming uncontrolled. The drying process takes 3 to 6 weeks depending on climate. Once dried, the outer layers are mechanically removed to reveal the green bean, which has been absorbing the fruit sugars throughout the long drying process.
What it does to flavour: Extended contact between the bean and the fruit during drying transfers significant amounts of fruit sugars and organic compounds into the bean. The result is a sweeter, heavier, more fruit-forward coffee with distinctly different aromatics from a washed lot of the same origin.
Flavour profile: Rich fruit sweetness , berries, stone fruit, dried fruit. Heavy body. Lower perceived acidity (though acidity may be similar , it is masked by sweetness). Sometimes fermented or wine-like notes. Less clarity in the cup but more sensory complexity.
Origin association: Ethiopia (particularly Sidama and Guji zones), Brazil (dominates production), Yemen, some Central American experimental lots. Natural processing requires dry, consistent weather for 3-6 weeks , it is not viable in humid climates without significant infrastructure.
In our range: The Ethiopian Basha Bekele is a natural-processed lot , the wild berry, jammy fruit and floral character in this coffee are signatures of natural processing from Ethiopian highland farms.
3. Honey Processing
How it works: Honey processing is a middle path between washed and natural. The cherry skin is removed (pulped) as in the washed process, but some or all of the mucilage is left on the bean during drying , it is not washed off. The "honey" name comes from the sticky appearance of the mucilage-coated beans. The amount of mucilage left on the bean determines the type of honey process: yellow honey (little mucilage), red honey (moderate), and black honey (most mucilage, closest to natural).
What it does to flavour: Honey processing captures the best of both worlds , the cleanliness and brightness of washed processing, with some of the sweetness and body from the fruit sugars. The result is typically sweeter than washed but cleaner than natural, with a medium body and appealing rounded quality.
Flavour profile: Sweet, caramel-like. Stone fruit notes (peach, apricot, nectarine). Medium body. More clarity than natural but more sweetness than washed. The specific profile depends on how much mucilage was left , yellow honey will be closest to washed; black honey closest to natural.
Origin association: Costa Rica (where the method was pioneered), El Salvador, Guatemala, Panama. Growing in popularity across Central America and increasingly in Ethiopia and Colombia.
Brewing recommendation: Honey-processed coffees perform beautifully as pour-overs and in the cafetière. Their sweetness and medium body translate well across both immersion and filter brewing.
4. Anaerobic Processing
How it works: Anaerobic processing is the most recently developed method and the most experimental. Coffee cherries (either whole or pulped) are sealed in airtight fermentation tanks with no oxygen present. The absence of oxygen fundamentally changes the fermentation environment, encouraging different microbial activity than aerobic (open-air) fermentation. Fermentation is often temperature-controlled and can last from 24 hours to several weeks. After fermentation, the beans are dried using either washed or natural methods.
What it does to flavour: Anaerobic fermentation produces a highly distinctive flavour profile , intense, often unusual, sometimes polarising. The specific flavours depend on the fermentation time, temperature, yeast strains present and the processing decisions made after fermentation. The result can range from intense tropical fruit to wine-like to fermented and funky.
Flavour profile: Intense and unusual. Tropical fruit (mango, pineapple, passionfruit). Wine-like. Sometimes fermented or "boozy" notes. Very heavy body. High sweetness. Not for drinkers who prefer traditional, clean coffee flavours , but one of the most exciting developments in speciality coffee for those who enjoy experimentation.
Origin association: Increasingly common across all producing regions. Particularly prominent in Colombia, Panama and Ethiopia as producers experiment with fermentation to differentiate their lots in the speciality market.
Brewing recommendation: Anaerobic coffees are best explored as filter coffees (pour-over, AeroPress) where the nuanced and unusual flavours have room to develop without the pressure and concentration of espresso extraction.
5. Wet-Hulled (Giling Basah) Processing
How it works: Wet-hulling is a processing method unique to Indonesia , particularly Sumatra, Sulawesi and Aceh. The cherry skin is removed while the beans still have high moisture content (around 40-50%). Unlike other methods, the parchment layer is removed while the beans are still partially wet , much earlier in the drying process than is standard. The beans are then dried to their final moisture content without the parchment protection. This unique process is driven by the humid Indonesian climate, which makes extended drying with the parchment intact extremely difficult without risking mould and defects.
What it does to flavour: Removing the parchment while the bean is still moist exposes it to oxygen and the environment during the final drying stage. This produces the distinctive earthy, herbal, spicy character that Indonesian coffees are famous for , a flavour profile found nowhere else in the world.
Flavour profile: Full body. Very low acidity. Earthy, herbal, dark spice. Tobacco, cedar, dried fruit. A savoury depth unlike any other processing method. Some describe it as "mossy" or "forest floor" , characteristics that sound unappealing in description but are remarkably compelling in the cup for those who appreciate it.
Origin association: Indonesia . Sumatra (Mandheling, Lintong), Sulawesi (Toraja), Aceh (including Gayo). This is the method that gives Sumatran coffee its characteristic weight and earthiness.
In our range: The Indonesian Burni Telong from Aceh is wet-hulled. Its earthy depth, full body and low acidity are direct products of Giling Basah processing. One of the most distinctive coffees in our range.
How Processing Affects Flavour . A Practical Summary
Acidity
Washed coffees typically have the highest perceived acidity , bright, clean, lively. Natural coffees have lower perceived acidity because sweetness masks it. Honey-processed coffees sit between the two. Wet-hulled (Indonesian) coffees have the lowest acidity of any processing style.
Body
Natural and wet-hulled coffees have the heaviest body , the oils and compounds from extended fruit contact or unique processing create a thick, syrupy mouthfeel. Washed coffees are lighter-bodied and cleaner. Honey process sits in the middle.
Sweetness
Natural processing produces the sweetest coffees , the fruit sugars absorbed during extended drying are directly detectable. Honey process follows closely. Washed coffees can be sweet but express it differently , more as clean sugar than as fruit-forward sweetness.
Fruit Notes
Fruit notes are most prominent in natural-processed coffees (berries, stone fruit, dried fruit) and some honey-processed lots (peach, apricot). Washed coffees can have citrus and floral notes but they are different in character , lighter and more delicate rather than the jammy intensity of a natural lot.
Clarity and Transparency
Washed coffees are the most "transparent" , the cup clearly expresses the character of the bean, its variety, and terroir. Natural-processed coffees are more opaque , the processing character dominates. Some coffee drinkers prefer the transparency of washed; others prefer the complexity of natural. Both are valid , they are different experiences rather than different quality levels.
We Are Coffee Co's Approach to Processing
Sourcing from Known Farms
We do not buy anonymous lots. Every coffee in our range is traceable to a specific farm or cooperative, which means we know exactly how it was processed, who did the processing, and under what conditions. Processing quality varies enormously , a natural-processed coffee requires more skill, attention and infrastructure than the description suggests, and poor natural processing produces fermenty, defective cups rather than beautiful fruit character.
When we buy a natural-processed lot, we know the producer's track record with natural coffees, the climate conditions that season, and the specific drying infrastructure they used. That knowledge is reflected in the quality and consistency of what arrives in your bag.
Processing and Flavour Transparency
We describe the processing method on every single-origin product page because we believe it is relevant information for coffee drinkers who want to make informed choices. If you have tried our Ethiopian Basha Bekele (natural) and loved the fruit character, you now know to look for natural-processed coffees from East Africa across our range. If you preferred the clarity of the Colombian Inza Pedregal (washed), you know washed Central and South American coffees are likely your territory.
Consistency Across Harvests
Processing at farm level is affected by climate , a wet season can make natural processing impossible, forcing a farm to pivot to honey or washed methods. When this happens, the same farm's coffee can taste different from year to year. We flag these changes and provide updated flavour notes when the processing method shifts between harvests. Transparency is the standard.
Frequently Asked Questions
What is the difference between washed and natural coffee?
Washed coffee has the fruit cherry removed before drying, and the mucilage washed off with water. This produces a cleaner, brighter cup that more transparently expresses the origin character of the bean. Natural (dry) processed coffee dries with the whole cherry intact around the bean , this transfers fruit sugars into the bean during the drying process, producing sweeter, fruitier, heavier-bodied cups. Both methods can produce exceptional coffee, but they produce very different flavour profiles even from the same origin and farm.
Does processing method affect caffeine content?
No , processing method has essentially no effect on caffeine content. Caffeine is a stable alkaloid that is not materially affected by the fermentation, washing or drying processes. Caffeine content is primarily determined by the coffee variety (Robusta has roughly twice the caffeine of Arabica), roast level (very slightly higher in lighter roasts, though the difference is minimal), and grind/brew ratio. If you are adjusting your coffee intake for caffeine reasons, focus on variety and dose rather than processing method.
What is honey process coffee?
Honey process is a middle path between washed and natural processing. The cherry skin is removed (as in washed), but some or all of the sugary mucilage layer is left on the bean during drying (unlike washed, where it is cleaned off). The "honey" name comes from the sticky, honey-like appearance of the mucilage-coated beans. The result is a coffee with more sweetness and body than a washed lot from the same farm, but more clarity and cleanliness than a naturally dried one. Honey-processed coffees often show stone fruit characteristics , peach, apricot, nectarine , and a pleasant rounded sweetness.
What is anaerobic coffee and why is it so different?
Anaerobic processing ferments the coffee cherry in sealed, oxygen-free tanks rather than in open air. The absence of oxygen creates a very different fermentation environment , different microbial strains dominate, different organic compounds are produced, and the resulting flavour profile can be dramatically more intense and unusual than conventional processing methods. Anaerobic coffees often show intense tropical fruit, wine-like or "boozy" notes. They are polarising , some drinkers love their intensity; others prefer traditional flavour profiles. They are best experienced as filter coffees (pour-over, AeroPress) where the unusual notes can be appreciated at full clarity.
Why do Indonesian coffees taste so different from other origins?
The unique character of Indonesian coffees , the earthiness, full body, low acidity and dark spice , is primarily a product of wet-hulled processing (Giling Basah), which is unique to Indonesia. In this method, the parchment layer is removed while the bean is still partially wet, exposing it to oxygen during final drying in a way that no other processing method does. The humid Indonesian climate made this method a practical necessity, but the flavour it produces is now one of the most prized and distinctive styles in speciality coffee. Our Indonesian Burni Telong from Aceh is a classic example.
Which processing method makes the best coffee?
There is no single best method , it depends entirely on preference and context. For drinkers who love bright, floral, complex flavours with high clarity, washed coffees from Ethiopia or Colombia are the benchmark. For drinkers who love rich fruit sweetness and body, natural-processed Ethiopian or Brazilian coffees are exceptional. For something in between, honey-processed Central American coffees offer a compelling middle ground. Wet-hulled Indonesian coffees are in a category of their own for those who love earthy, full-bodied, low-acid cups. The best approach is to try examples of each , the differences are not subtle, and you will quickly find your preference.
How does processing affect the best brew method for a coffee?
Processing method influences how a coffee performs in different brew methods. Washed coffees are highly transparent and perform exceptionally well as filter coffees (pour-over, AeroPress, Chemex) where their clarity and acidity can be fully expressed. Natural-processed coffees have more body and sweetness, which suits cafetière brewing and espresso well , the immersion or pressure extracts their richness fully. Honey-processed coffees are versatile. Wet-hulled Indonesian coffees are often recommended for cafetière and Moka pot, where their earthy, full-bodied character is most satisfying.
Explore Processing in Practice
The best way to understand processing is to taste the difference side by side. Try our Ethiopian Basha Bekele (natural) next to our Colombian Inza Pedregal (washed) , two exceptional coffees from two exceptional origins, with processing as the defining variable. The contrast is instructive.
For the full range of processing styles in one collection, explore our light roast and dark roast ranges. All coffees list the processing method on the product page , understanding what each method means will change how you read every coffee description you encounter from now on.
Free delivery on orders over £25. All coffees flame-roasted in small batches in Glasgow, SCA-scored, and dispatched within days of roasting.
