Understanding Coffee Processing

Coffee processing determines how the fruit surrounding the seed is removed after harvest. This decision profoundly impacts the final cup profile. The three foundational categories are seed dried (washed), mucilage dried (honey), and fruit dried (natural). Each method manipulates fermentation, drying time, and how much fruit matter remains on the seed during drying.

Seed Dried: Washed Processing

Washed processing removes all fruit matter before drying begins. Cherries are depulped mechanically within hours of harvest. The seeds, still coated in a sticky mucilage layer, move to fermentation tanks. Fermentation breaks down the remaining mucilage over 12-72 hours depending on ambient temperature and desired flavor development.

After fermentation, seeds are washed clean and dried on patios or raised beds until they reach 10-12% moisture content. This typically takes 7-14 days.

Flavor Impact: Washed coffees emphasize clarity and terroir. You taste the varietal characteristics and growing conditions more directly. Acidity is bright and well-defined. Body tends toward tea-like or silky rather than syrupy.

Good examples of washed coffees

• Aricha Adorsi 
• Marcellesa 

Mucilage Dried: Honey Processing

Honey processing removes the skin and some pulp but leaves varying amounts of mucilage on the seed during drying. The mucilage is sugar-rich and sticky—hence the name "honey," though no actual honey is involved.

There are several honey process variations:

1. White Honey: 80-90% of mucilage removed. Dries quickly (8-10 days). Closest to washed in profile.
2. Yellow Honey: 50-75% mucilage removed. Moderate drying time (10-12 days). Light fruit sweetness emerges.
3. Red Honey: 25-50% mucilage removed. Slower drying (12-15 days). Notable body and fruit-forward sweetness.
4. Black Honey: Minimal mucilage removal (10-25%). Slowest drying (15-20+ days). Maximum sweetness and body. Requires careful monitoring to prevent over-fermentation.

The more mucilage retained, the longer the drying time and the greater the fermentation activity. This creates more complex sugars and fuller body.

Flavor Impact: Honey processing bridges washed and natural. Expect more sweetness and body than washed, but more clarity than natural. Fruit notes are present but defined. Acidity is softer and rounder than washed coffees.

Fruit Dried: Natural Processing

Natural processing is the oldest method. Whole cherries are dried intact with no mechanical removal of fruit. Cherries are spread on raised beds or patios immediately after sorting and floater removal.

Modern natural processing involves careful cherry selection and meticulous drying management. Cherries are turned frequently—sometimes every 30-60 minutes during peak sun hours—to ensure even drying and prevent mold. Total drying time ranges from 15-30 days depending on climate and cherry density on beds.

Some producers soak cherries in water for 8-12 hours before drying to remove low-density floaters and equalize moisture content. This creates more consistent fermentation conditions.

Flavor Impact: Natural processing produces the most fruit-forward profiles. Expect pronounced berry, stone fruit, or tropical fruit notes. Body is fuller and syrupy. Sweetness is intense. Acidity integrates into the fruit character rather than standing separately. The extended contact between seed and fermenting fruit matter creates complex flavor compounds not possible in washed processing.

Example: The Ethiopia Natural Yirgacheffe demonstrates how high-elevation natural processing with extended 28-day drying creates layered fruit complexity with notes like cherry cola, creamsicle, and black currant.

Wet-Hulled: Giling Basah

Wet-hulled processing is specific to Indonesia, particularly Sumatra. Cherries are depulped and fermented briefly (8-12 hours). Unlike washed processing, the parchment layer is removed while the seeds are still at 30-35% moisture content—much wetter than standard dried parchment at 10-12%.

The wet, naked seeds are then dried to final moisture content. This process happens quickly, often in just 2-3 days, and under inconsistent conditions.

Flavor Impact: Wet-hulling creates the characteristic "Sumatran profile"—earthy, herbaceous, with low acidity and heavy body. The process is less about showcasing fruit or terroir and more about creating a specific rustic flavor signature. Notes of cedar, tobacco, dark chocolate, and forest floor are common.

Anaerobic Processing

Anaerobic processing manipulates fermentation by controlling oxygen exposure. Cherries or depulped seeds are placed in sealed tanks, creating an oxygen-free environment. This changes which microorganisms are active during fermentation and which flavor compounds they produce.

Anaerobic Natural: Whole cherries ferment in sealed tanks for 48-120 hours before drying naturally.

Anaerobic Washed: Depulped seeds ferment in sealed tanks before washing and drying.

Double Anaerobic: Where both of the above techniques are used.

Tank pressure, temperature, duration, and whether CO2 is purged all affect outcomes. Some producers add specific yeasts or bacteria cultures to further control fermentation.

Flavor Impact: Anaerobic fermentation produces unique flavor compounds not found in traditional processing. Expect intense fruit fermentation notes—think wine-like characteristics, boozy notes, or unusual fruit expressions like lychee or passion fruit. Profiles can be polarizing. When done well, they're complex and memorable. When overdone, they can taste artificially flavored or unpleasantly funky.

Good Anaerobic examples:

• Bombon 

Carbonic Maceration

Borrowed from winemaking, carbonic maceration involves flooding sealed tanks with CO2 and fermenting whole cherries under pressure. This creates fermentation inside the cherry itself—intracellular fermentation—rather than just in the surrounding environment.

Duration typically ranges from 3-10 days at controlled temperatures. After CM fermentation, cherries are dried naturally or processed as washed.

Flavor Impact: Carbonic maceration produces pronounced aromatic complexity. Expect floral notes, bright fruit candy characteristics, and elevated perceived sweetness. The process amplifies fruity esters and creates silky texture. Profiles often show tropical fruit, red berries, and pronounced florals.

Extended Fermentation & Controlled Fermentation

Beyond anaerobic and CM, producers are experimenting with extended fermentation times and precise environmental controls:

1. Thermal Shock: Alternating hot and cold temperatures during fermentation
2. pH Monitoring: Ending fermentation at specific pH targets
3. Yeast Inoculation: Adding specific cultured yeasts rather than relying on ambient microbes
4. Multi-Stage Fermentation: Different fermentation environments in sequence

These techniques allow producers to target specific flavor outcomes with more consistency than traditional methods.

How Processing Affects Your Cup

Processing is one of three primary flavor determinants, alongside varietal and terroir. The same coffee processed three different ways will taste dramatically different.

1. Washed: Highlights origin and varietal. Choose this when you want to taste what the soil and climate contributed.
2. Honey: Balances origin character with fruit sweetness. Choose this for approachable complexity.
3. Natural: Maximizes fruit intensity and body. Choose this when you want bold, fruit-forward coffee.
4. Wet-Hulled: Creates earthy, low-acid profiles. Choose this for rustic, full-bodied brewing.
5. Anaerobic/Experimental: Produces unique, often intense flavors. Choose this when you want something unexpected.

Processing & Brewing

Different processing methods benefit from different brewing approaches:

• Washed coffees excel in pour-over methods that highlight clarity—V60, Chemex, Kalita Wave. Higher temperatures (96-100°C) extract the clean acidity effectively.
• Natural and honey coffees work well in immersion methods—French press, AeroPress—that capture body and sweetness. Slightly lower temperatures (92-96°C) prevent over-extraction of the fruit sugars.
• Anaerobic and experimental coffees often benefit from lower temperatures (88-92°C) and coarser grinds to manage intense flavors.

The Future of Processing

Processing innovation is accelerating. Producers treat post-harvest handling as craft, not just commodity preparation. Expect more precise fermentation control, hybrid methods combining multiple approaches, and processing tailored to specific flavor targets.

The line between processing methods continues to blur. A "washed" coffee might involve 72-hour controlled fermentation. A "natural" might use thermal shock and pH monitoring. The terminology matters less than understanding how each decision affects flavor.

Processing transforms coffee from agricultural product to specialty beverage. Whether you prefer the clarity of washed, the balance of honey, the fruit intensity of natural, or the experimental edge of anaerobic, understanding processing helps you choose coffees you'll love.

Start by identifying which processing methods appeal to your palate. Then explore how different origins express those methods. A natural Ethiopian tastes nothing like a natural Colombian—but both share that fruit-forward intensity that defines fruit-dried processing.

Browse our complete coffee collection  to explore different processing methods and discover your preferences.