Learn about coffee - Processing – Sandbox Coffee Roasters

STEP 3 OF 5 - PROCESS

Person working in a field with red co using a tool.fee cherries

From fruit to green bean

Every coffee starts as a fruit. Processing is everything that happens between picking that cherry and the green bean reaching a roaster — and it is one of the biggest drivers of what ends up in your cup.

The processes below range from centuries-old traditions to techniques invented in the last decade. Some let nature do the work. Others involve sealed tanks, temperature-controlled labs, and microbiology. All of them start with the same cherry.

Growing

Harvest

Processing

Roasting

Brewing

THE BASICS

What processing actually does

Inside every coffee cherry is a seed — what we eventually roast and grind. Processing is how that seed is extracted and dried. The key variable is how much of the surrounding fruit is left in contact with the bean, and for how long. More fruit contact means more fermentation, more sugar transfer, more intensity. Less means cleaner, brighter, more transparent flavor. Every method is a point somewhere on that spectrum.

Worker raking coffee beans drying under the sun at a scenic coffee farm

Tier 1 — Classic

Where it all started. The foundation of most coffee in the world.

Natural

Dry process

The whole cherry is dried in the sun with the fruit still on — for weeks. Sugars from the fruit slowly infuse into the bean. The result is heavy body, low acidity, and intense fruit character. The oldest method in the world, and still one of the most expressive.

Washed

Wet process

The fruit is removed before drying. The bean is fermented in water to strip away any remaining pulp, then washed clean and dried. With almost no fruit influence left, the terroir of the bean — soil, altitude, variety — comes through with unusual clarity. Bright, clean, high acidity.

Honey

Pulped natural

A middle path. The skin is removed but a sticky layer of fruit mucilage is left on the bean during drying. More sweetness and body than washed, more clarity than natural. Yellow, red, and black honey refer to how much mucilage remains and how long drying takes.

Tier 2 — Controlled

Producers taking deliberate control of fermentation conditions.

Double Layer Natural

Stacked drying

Cherries are stacked in two layers during drying — a deliberate choice that creates different fermentation conditions between the layers. The lower layer develops more slowly, building complexity. The result is layered, often wine-like, with more depth than a standard natural.

Anaerobic Natural

Sealed fermentation

Whole cherries ferment in sealed, oxygen-free tanks before drying. Without oxygen, specific microorganisms produce distinctive aromatic compounds — often tropical, fermented, or wine-like. High risk, high reward: precision is everything.

Anoxic Washed

Sealed fermentation

Like anaerobic, but the fruit is removed before the sealed tank. The result is cleaner and more controlled than an anaerobic natural — fermented complexity without the heavy fruit body. Vivid, structured, and often florally aromatic.

Carbonic Maceration

CO₂ fermentation

Borrowed from winemaking. Whole cherries ferment in a CO₂-saturated environment, which triggers fermentation inside the fruit itself rather than from the outside in. The result is unusually clean and vibrant — bright acidity, vivid aromatics, a very distinctive texture in the cup.

Tier 3 — Experimental

Where the boundaries of what coffee can taste like are still being drawn.

Co-Fermented

Added ingredients

Cherries ferment alongside added ingredients — fruit juice, spices, botanicals — which introduce specific flavor compounds into the bean. The coffee takes on characteristics of whatever it fermented with. Polarising, intentional, and completely unlike anything that came before it.

EF2

Extended fermentation

A two-stage extended fermentation protocol developed at Granja Paraíso 92 in Colombia. The cherry is fermented twice — first with fruit on, then after pulping — each stage held at a precise temperature for a precise duration. The result is extraordinary complexity with unusual clarity.

Thermal Shock

Temperature treatment

Not a fermentation method on its own — a finishing step. After fermentation, cherries are briefly immersed in hot water, then immediately in cold. The rapid temperature change opens the bean's pores, then seals them, locking in the aromatic compounds developed during fermentation. The result is remarkable clarity and vivid sweetness.

Key takeaway

Same cherry, different cup

Take two bags from the same farm, the same harvest, even the same tree. Process one as a washed and the other as a natural. Brew them side by side. They will taste like completely different coffees. Processing does not just affect flavor — it defines it. It is why the same origin can show up in your cup as something bright and citrusy one month, and rich and jammy the next.