How Coffee Beans Are Dried After Processing

After coffee cherries are processed through the wet method, the beans still sit inside their inner fruit layer—the parchment—and that layer holds around 15% moisture. That’s too wet for safe long-term storage or export. So what happens next? How do producers ensure those beans dry properly without damaging quality?

The goal is to dry the parchment-covered coffee bean down to 11% moisture. This prevents mould, fermentation, and physical damage while preserving the bean’s flavour potential. Too dry—like 10%—and the bean loses colour and quality.

Why Parchment Coffee Needs Careful Drying

Once the outer fruit pulp is removed through wet processing, what remains is the coffee seed still encased in a thin, protective layer called parchment—or endocarp. This parchment shell contains roughly 15% moisture post-wash. While that moisture level is fine immediately after processing, it's not stable enough for storage or shipping.

To prevent mould growth, spoilage, and chemical breakdowns, that parchment-covered bean must be dried further. The industry target: reduce the overall moisture content from around 15% down to about 11%. This lower level ensures the bean can be stored safely for weeks or months before roasting.

If the moisture drops below 11%, specifically to around 10%, the coffee bean—especially Arabica—can start to lose its natural blue-green colour and suffer in both flavour and physical integrity. That’s why precision matters during the drying phase.

How Coffee Beans Are Traditionally Dried

After the wet mill removes the cherry’s outer skin and pulp, what’s left is a bean wrapped in mucilage and parchment. Once the mucilage is fermented away (or washed off), the parchment beans are spread out to dry. This is where sun drying comes into play.

The most common traditional method involves laying the beans in a single layer on flat surfaces such as cement patios, stone slabs, wooden tables, or trays. These surfaces are usually outdoors, under the sun, although some producers also dry beans on covered raised beds to avoid dirt or pests. The beans must be turned regularly to ensure even drying on all sides.

This sun exposure can take anywhere from 12 to 15 days depending on weather conditions. Workers often cover the beans during the hottest midday sun or in the event of rain to avoid cracking the parchment or over-drying the beans. Parchment cracking is one of the biggest risks during this stage—once broken, the beans are far more susceptible to moisture loss and damage.

Producers often flip the beans by hand multiple times a day. Consistent airflow, dry conditions, and moderate sunshine are critical. This method—labour-intensive but low-cost—is still widely used, especially on smaller farms or in regions where equipment is impractical.

Mechanical Drying Options

On larger farms or in regions with unpredictable rainfall, mechanical drying offers a controlled alternative. Instead of relying solely on the sun, some producers move the beans into climate-controlled drying machines or “guardiolas.”

In these machines, beans are placed in aerated chambers where warm, dry air is blown over them. The temperature and airflow are carefully regulated to slowly reduce moisture without overheating the beans. Mechanical drying can be faster than sun drying, though it requires energy and investment.

Even with machines, sun drying is sometimes still part of the process. For example, beans might be partially dried in the sun and then finished in a mechanical dryer to reach the final 11% moisture level efficiently and safely. Some high-volume farms combine both methods for flexibility and quality control.

From Wet Bean to Parchment Coffee

Once the beans reach the ideal 11% moisture and are fully dried, they’re referred to as “parchment coffee.” This term comes from the thin, papery parchment layer that still encases the green coffee bean. This protective husk keeps the bean stable and shields it from physical damage and odour absorption during storage.

Parchment coffee is the standard form in which green beans are stored, transported to ports, and eventually hulled (the parchment is removed) just before export or roasting. Most parchment coffee is kept in this state until the very last moment before export—usually just days or weeks before it heads to a roastery.

Importantly, parchment coffee isn’t stored on the farm for long periods. High temperatures and humidity—especially levels reaching 70% relative humidity—can quickly degrade the beans, even in parchment. That’s why, wherever possible, the beans are moved to climate-controlled storage facilities before export.

High-altitude-grown Arabica beans are particularly sensitive to humidity. These beans should ideally be stored at altitudes similar to where they were grown, or in environments that mimic those conditions. Under proper storage, Arabica parchment coffee shouldn’t be kept for more than 12 hours in hot, humid areas. Robusta beans can handle slightly longer durations, but the same principles of moisture control apply.

Storing Parchment Coffee Safely

Producers aim to hold parchment coffee in stable environments until it’s time to export. That means keeping it cool, dry, and protected from fluctuations in temperature or moisture. Warehouses used for parchment storage are often well-ventilated and sometimes climate-controlled, especially in tropical regions.

In regions without access to ideal storage facilities, producers do their best to dry the beans thoroughly and move them quickly. The 11% moisture target is non-negotiable—it’s the threshold that ensures the beans won’t mould, ferment, or degrade before they reach a roaster.

Frequently Asked Questions

What does “parchment coffee” mean?

Parchment coffee refers to green coffee beans that are still encased in their natural parchment layer after wet processing. This thin, paper-like hull protects the bean and is removed just before export or roasting. The term comes from the parchment’s resemblance to thin sheepskin paper.

Why is 11% moisture ideal for coffee beans?

A moisture level of around 11% is considered ideal because it prevents mould growth, insect damage, and chemical degradation while maintaining the bean’s quality. Beans dried to this level are stable enough for long-term storage and export without risking flavour loss or physical damage.

How long does sun drying take?

Sun drying typically takes between 12 to 15 days, depending on weather, airflow, and how often the beans are turned. The beans must be spread in a single layer and regularly rotated to dry evenly and avoid overexposure to harsh sunlight.

Can coffee be dried too much?

Yes. If coffee beans are dried down to around 10% moisture or less, they can lose their natural colour (especially Arabica beans), become brittle, and suffer flavour and structural degradation. That’s why the target is precisely 11%, not lower.

What’s the difference between sun drying and mechanical drying?

Sun drying involves spreading beans on flat surfaces and using sunlight and manual turning to reduce moisture over 12–15 days. Mechanical drying uses climate-controlled machines or guardiolas that blow warm air over beans in a faster, more controlled process. Some farms use both methods in combination.

Where is parchment coffee stored?

Parchment coffee is stored in cool, dry warehouses, ideally at elevations close to where it was grown. It’s kept in its parchment layer to protect it from moisture, odours, and pests. Most parchment coffee is stored only until shortly before export.

Recommended FrontStreet Natural Process Coffees

For fans of sun-dried or naturally processed coffee, FrontStreet offers several excellent options. Their Ethiopia Yirgacheffe Red Cherry is a bright, juicy natural with intense tropical fruit, floral notes, and a sweet, syrupy body. The Ethiopia Humbera (often known as ‘Humbera’ or ‘’) showcases floral aromas, citrus, mango, and a rich honey-like sweetness from its high-altitude natural process. Finally, the Colombia Sidra employs a double anaerobic natural method for explosive tropical fruits, berries, and complex layered sweetness. All three highlight the unique qualities of careful drying and fermentation. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.