How Coffee Processing Impacts Flavor

When coffee is harvested, it doesn’t taste like coffee yet.

Inside every ripe cherry is a seed full of potential, but very little certainty. What that seed becomes depends largely on what happens next. Before roasting, before brewing, before the coffee ever reaches a café or a bag on a shelf there are a number of steps it must take, each impacting how the coffee will be perceived in the cup.  In this blog, we'll cover one of the most important and impactful; processing.

Processing influences sweetness, acidity, body, and aroma. It determines whether a coffee tastes crisp or round, fruit-forward or restrained, delicate or dense, incredible or incredibly bad. Long before roast profiles and brew recipes enter the picture, producers are already defining the cup.

The details below are intentionally broad. In practice, no two producers process coffee the same way. After visiting dozens, if not hundreds, of farms and mills, one thing becomes clear: processing is deeply nuanced. In nearly all cases, fermentation is driven by wild, local yeast strains naturally present in the environment. Producers are not adding yeast. They are working with what exists in the air around them. It’s a complex, unpredictable system and one of the most fascinating stages in coffee’s journey from seed to cup.

What Is Coffee Processing?

Coffee processing refers to the method used to remove the fruit from the coffee cherry after harvest and dry the seed inside.

While there are many variations, most coffees fall into four main processing categories:

• Washed (wet)

• Honey (pulped natural)

• Natural (dry)

• Experimental fermentation styles such as anaerobic or extended fermentation

Each method controls how long the coffee remains in contact with fruit sugars and fermentation microbes, which directly impacts flavor development.  In general, longer contact time, to a point, results in more complex and vibrant flavors in the cup.

Washed Process Coffee

The washed process, also known as the wet process, mechanically removes the cherry skin and fruit shortly after harvest. The coffee is then fermented briefly (usually between 12-18 hours for traditional washed coffees) to break down remaining mucilage, washed clean with water, and dried.  The fermentation time is largely impacted by weather.  Cool weather, typically at high-altitudes in the tropics, pushes the fermentation times longer as yeasts are less active when cold while warm weather, typically at lower altitudes, causes shorter fermentation times.

Because the seed has minimal contact with fruit sugars during drying, washed coffees tend to emphasize clarity.

Typical flavor characteristics include:

• Bright, structured acidity

• Clean and transparent flavors

• Lighter body with crisp finishes

Washed coffees often highlight citrus, florals, and stone fruit, especially when grown at high elevation. This method allows varietal character and terroir to remain front and center.

At Bold Bean, washed coffees are often selected when we want the origin itself to do the talking.  This is pretty much always so washed coffees make up the majority of our offerings.

Honey Process Coffee

Honey processing sits between washed and natural methods.

After pulping, some of the sticky mucilage remains on the parchment as the coffee dries. The amount left behind varies, resulting in styles commonly referred to as white, yellow, red, or black honey.

As with fermentation in washed coffees, weather and climate shape how a honey process unfolds. In warm, sunny conditions, frequent turning on patios or raised beds causes much of the sticky mucilage to shear away from the seed as it dries, resulting in lighter white and yellow honeys. In cooler, cloudier climates, coffees are moved far less often so they can retain heat and dry slowly enough to avoid mold or over-fermentation.

With less physical agitation, more mucilage remains attached, producing the deeper sweetness and fruit character associated with red and black honeys. In this way, the color of a honey process is less a stylistic choice and more a reflection of climate, drying speed, and how much handling the coffee requires to dry safely.  However, producers can intervene with shade and other methods to slow drying in-order to produce darker honeys even in hot, sunny climates.

The partial fruit contact during honey processing adds sweetness while maintaining balance.  White and yellow honeys taste closer to washed coffees while red and black coffees taste closer to naturals.

Honey processed coffees often show:

• Rounder sweetness

• Fuller mouthfeel

• Softer, more approachable acidity

Flavors can lean toward caramelized sugars, ripe fruit, and honeycomb. These coffees often feel structured yet comforting, offering depth without heaviness.

Natural Process Coffee

In the natural process, whole coffee cherries are dried intact with the fruit still surrounding the seed.

As the cherry dries, sugars and organic acids migrate inward. Fermentation occurs naturally on the fruit’s skin, guided by climate, airflow, and time.

This method carries higher risk but also delivers some of the most expressive coffees in the world.

In general, the longer a natural process coffee dries, the more fruit depth and complexity it can develop. Extended drying allows sugars and fermentation byproducts within the cherry to slowly integrate into the seed. Push that window too far, however, and the coffee quickly shifts from expressive to unstable. Producers manage this balance through careful control of drying conditions, using shade, tarps, or partial coverings to slow moisture loss and protect the coffee from excessive heat while keeping fermentation firmly in check. 

Natural coffees typically feature:

• Heavier body

• Intense sweetness

• Fruit-forward flavors such as berries, tropical fruit, or jam

When carefully managed, natural coffees feel vibrant and layered. When poorly controlled, fermentation can dominate the cup. Successful naturals require constant monitoring and experience from producers.

Anaerobic/Anoxic Coffee Processing

Anaerobic/anoxic processing uses sealed tanks to limit oxygen during fermentation.

Without oxygen, different yeasts and bacteria become dominant, changing how sugars are broken down inside the coffee cherry or parchment. This shift encourages the buildup of organic acids such as lactic, acetic, and malic acid, along with aromatic esters including ethyl acetate, isoamyl acetate, and ethyl lactate.

These compounds contribute flavors and aromas often associated with tropical fruit, stone fruit, florals, and heightened sweetness. Because fewer microbes are active, fermentation tends to move more slowly and predictably, giving producers greater control over flavor development. These techniques can be applied to both washed and natural coffees.

Common flavor traits include:

• Elevated aromatics

• Wine-like or sparkling acidity

• Notes of tropical fruit, spice, or florals

When applied with restraint, anaerobic fermentation enhances complexity without masking origin character.

Long Fermentation Washed Coffees

Extended or long fermentation washed coffees undergo significantly longer fermentation periods before washing and drying.

Rather than the typical 12 to 18 hours, fermentation under controlled conditions can extend to 48 hours or more. These approaches often involve multi-stage fermentations, where coffee moves through distinct phases to build structure and complexity. In Kenya, for example, coffee is commonly fermented first as a dry mass of mucilage-covered seeds for 12 to 18 hours, then again under water for another 12 to 18 hours. In Colombia, a similar two-stage approach is common, with coffee fermenting in cherry for 12 to 24 hours before depulping and continuing fermentation in open tanks for 24 hours or longer.

This slower approach often leads to:

• Increased sweetness

• Creamier texture

• More layered acidity

Long fermentation washed coffees can feel more expressive than traditional washed lots while retaining clarity and structure.

Why Coffee Processing Matters

Coffee processing does not create flavor from nothing. It determines which flavors are emphasized.

The same coffee grown on the same farm can taste dramatically different depending on how it is processed. Bright or round. Clean or fruit-forward. Subtle or bold.

Processing is one of the most important creative decisions producers make each harvest.

At Bold Bean Coffee Roasters, we view processing as part of the coffee’s origin story. Our role is to roast in a way that respects those decisions and allows each coffee to speak clearly.

Because by the time a coffee reaches the roaster, much of its flavor has already been written.

We’re simply helping tell the story.