Natural, Washed, Honey, Sumatra method—How do processing methods change the taste of coffee?
When buying coffee beans,
"Natural"
"Washed"
"Honey"
Have you ever seen these words?
For Indonesian coffee,
"Giling Basah"
may also be written.
These all refer to the processing method used to produce green beans from harvested coffee cherries.
In fact, the taste of coffee is not only determined by its origin, variety, or roasting.
How the pulp is removed, fermented, and dried after harvesting—
This difference can greatly alter the taste of coffee, even for beans from the same region and of the same variety.
This time, we will introduce four representative processing methods.
① Washed
Washed processing involves removing the skin and pulp from harvested coffee cherries, then removing the mucilage remaining around the seeds through fermentation before drying them.
Its main characteristic is:
Cleanliness and clarity of flavor.
Compared to natural processing, where the fruit is dried for a long period, washed processing results in less strong fermentation or fruit-derived flavors, making it easier to discern the inherent characteristics of the region and variety.
Generally, it tends to result in:
・Cleanliness
・Bright acidity
・Transparency
・Clean aftertaste
For beans with citrus acidity or floral aromas, these characteristics can be beautifully expressed.
"I want to see the inherent individuality of that coffee."
In such cases, 0566 sometimes considers washed processing as a benchmark.
② Natural
Natural processing is a very old method.
It involves drying harvested coffee cherries with the fruit still attached.
After sufficient drying, the dried skin and pulp are removed to extract the green beans.
Since the fruit and seeds remain in contact for a long period during drying and fermentation, the taste tends to be quite different from washed processing.
Generally, it tends to result in:
・Strong sweetness
・Berry-like notes
・Ripe fruit notes
・Tropical fruit notes
・Wine-like aroma
・Full-bodied mouthfeel
On the other hand, natural processing is also a difficult method to manage drying.
Uneven drying or excessive fermentation can lead to undesirable fermented odors and inconsistencies in quality.
That's why beautifully produced natural coffee has a unique appeal.
③ Honey
From the name, you might think, "Is honey used?" but no honey is used.
After removing the skin of the coffee cherry, this method involves drying the beans with some of the mucilage (sticky substance) around the seeds still intact.
This mucilage is sticky and looks like honey, which is why it's called "Honey Process."
In terms of flavor profile,
It can be described as a midpoint between the cleanliness of washed and the sweetness of natural.
Generally, it tends to result in:
・Sweetness
・Roundness
・Fruity notes
・Caramel or brown sugar nuances
・Moderate acidity
Of course, the taste varies depending on the amount of mucilage left and the drying method.
It is one of the processing methods where the producer's skill is clearly reflected in the taste.
④ Sumatra Method (Giling Basah)
And indispensable when discussing Indonesian coffee, especially from Sumatra, is
Giling Basah
In Japan, it is known as the "Sumatra method" or "wet hull."
In typical washed processing, the parchment—the shell around the bean—is fully dried while still on, and then removed.
However, with the Sumatra method, the parchment is removed while the beans still contain a lot of moisture.
Afterward, the green beans are dried further.
Why did such a unique method come about?
One major reason is Sumatra's hot and humid climate.
In a rainy and humid environment, it takes a long time to completely dry coffee.
Thus, a unique method evolved where the parchment is removed mid-drying to accelerate the process.
This Sumatra method can lead to:
・Heavy body
・Relatively mild acidity
・Earthy notes
・Herbal notes
・Spice notes
・Woody notes
・Dark chocolate notes
—flavors that we associate with "Mandheling-like" coffee.
What if the same coffee is processed in 4 ways?
This is where it gets interesting.
Even coffee of the same variety harvested from the same farm,
Washed
Natural
Honey
Sumatra method
will show different characteristics when processed using these methods.
In fact, a study that processed Sigarar Utang from North Sumatra using different methods also conducted sensory evaluations for Full Wash, Semi Wash, Honey, and Natural, achieving specialty-grade ratings for multiple processing methods.
In other words,
"Where it was made" alone does not determine the taste of coffee.
Variety, altitude, climate, harvesting, processing, drying, storage, and finally, roasting.
All of these contribute to a single cup of coffee.
Why 0566 brought back 4 types from Samosir Island
In August 2026, 0566 Coffee Production visited Samosir Island in North Sumatra, Indonesia.
While touring local processing plants, they confirmed that not only the traditional Sumatra method but also full washed, natural, and honey processing were being carried out.
Therefore, we brought back green beans processed using different methods to Japan.
The purpose is simple:
We want to actually roast and compare coffee from the same region.
Is it the individuality of the origin?
Is it the individuality of the variety?
Is it the individuality created by the processing?
We want to ascertain this for ourselves.
Which processing method is the most delicious?
The answer is,
"There isn't one best method."
I believe.
If you like transparency and bright acidity, choose washed.
If you like fruitiness and a fragrant aroma, choose natural.
If you seek sweetness and balance, choose honey.
If you want to enjoy a heavy body and the complex character typical of Sumatra, choose the Sumatra method.
There's joy in choosing according to your preference.
When selecting coffee beans, don't just look at the origin; please also pay attention to the "PROCESS" written on the bag.
The taste of coffee you've been casually drinking might look a little different from now on.
Quick Comparison of the 4 Processing Methods
Washed
Characteristics: Pulp removed before drying
Flavor Profile: Clean, bright acidity, transparency
Natural
Characteristics: Dried with the cherry intact
Flavor Profile: Fruity, sweet, wine-like aroma
Honey
Characteristics: Dried with mucilage remaining
Flavor Profile: Sweetness, roundness, fruity notes
Sumatra Method (Giling Basah)
Characteristics: Hulled while still containing high moisture, then further dried
Flavor Profile: Heavy body, mild acidity, herbal, spicy, earthy nuances
References and Information Sources
・Specialty Coffee Association "The Fermentation Effect"
https://sca.coffee/sca-news/25-magazine/issue-10/english/the-fermentation-effect-25-magazine-issue-10-bw558
・FAO "Coffee Processing/Techniques in Tapanuli Utara, Humbang Hasundutan, and Toba Samosir District"
https://www.fao.org/fileadmin/user_upload/agns/pdf/coffee/Annex-E.5.pdf
・Purba et al. "Sensory Quality and Hedonic Level of Sigararutang Arabica Coffee Brew on Varied Processing Treatment"
https://conference.lppm.unila.ac.id/index.php/icsiger/article/view/58
*The description of processing conditions on Samosir Island is based on interviews and research conducted by 0566 Coffee Production during their visit to local farms and processing plants in August 2026.
