How Small Coffee Beans Are Harvested and Processed

For coffee professionals and enthusiasts alike, one of the most critical questions is: how are high-quality coffee beans actually harvested and processed? In Yunnan, where small coffee beans—primarily Typica—are grown, the answer lies in precise timing during harvest and a carefully managed wet processing method. These steps directly influence the final cup profile, from acidity to sweetness.

The key takeaway: small coffee beans in Yunnan are typically harvested when the cherries turn fully red and processed using a nine-step wet method, including fermentation for 24–36 hours, drying for 5–7 days, and careful grading before export.

When to Harvest Small Coffee Beans

Harvest timing is crucial for both yield and quality. Small coffee beans—known for their small fruit size—have a relatively short and concentrated harvest window. The optimal time is when the coffee cherries turn red. Waiting longer risks overripening and fruit drop, so pickers harvest cherries as soon as they’re fully red, following a strict “pick-as-they-ripen” approach.

Why Harvest Timing Matters

Picking unripe or overripe cherries leads to inconsistent cup profiles, including undesirable bitterness or a lack of sweetness. Small coffee varieties, such as Typica, are especially sensitive to ripeness due to their smaller cherry size and thinner pulp. That’s why experienced farms in Yunnan emphasize harvesting only fully red, mature cherries.

How Wet Processing Works for Small Coffee Beans

Nearly all small coffee beans in Yunnan are processed using the washed (wet) method. This nine-stage process ensures cleanliness, consistency, and enhanced acidity. Here's how it works, step by step:

• 1. Wash the Cherries: Remove dirt and debris from the coffee cherries immediately after harvest.
• 2. Sort Fresh Cherries: Separate underripe (green), overripe (dry), damaged, and defective cherries. Use water tanks or screens to sort cherries by size and density.
• 3. Remove the Skin (Depulping): Use manual or mechanical depulpers. Hand-cranked machines process 35–40 kg/hour, small electric machines handle 250–400 kg/hour, and large commercial machines process up to 3–4 tons per hour.
• 4. Separate Parchment from Mucilage (Mucilage Removal): If not done by the depulper, separate the beans from the remaining fruit skin manually—workers can only manage about 26 kg per hour.
• 5. Ferment to Remove Mucilage: Soak the beans in water for 24–36 hours to break down the sticky mucilage layer. Stir and change the water every 12 hours.
• 6. Rinse Thoroughly: Wash the beans immediately after fermentation, usually in large washing basins to remove any leftover residue.
• 7. Dry the Beans: Spread the beans to dry in the sun on concrete patios or bamboo mats for 5–7 days, or use mechanical dryers. Consistent airflow and regular turning are essential.
• 8. Hull the Dried Beans (Dry Milling): Once the moisture level is safe and the beans pass sampling tests, remove the parchment layer to reveal the green coffee bean inside.
• 9. Grade and Package: Hand-sort to remove defects, then grade by size and density before packing as green coffee for export or roasting.

Common Equipment Used in Wet Processing

Different scales of farms use varying equipment. Manual or hand-cranked depulpers are common among smallholders, while larger estates invest in electric depulpers capable of handling several tons per hour. Fermentation tanks and concrete drying patios are standard, though some farms have shifted to raised beds or mechanical drying for better control.

Frequently Asked Questions

When is the best time to harvest small coffee beans?

The best time to harvest small coffee beans is when the cherries turn fully red. Harvesting should occur as soon as the cherries reach this stage to prevent overripening and fruit drop. Picking too early results in underripe beans, while leaving them too long on the branch leads to losses.

What is the wet processing method for coffee?

Wet processing, or washed processing, involves removing the coffee cherry’s skin and pulp, fermenting to remove the mucilage, washing, and then drying the beans. It typically includes nine steps: washing, sorting, depulping, mucilage removal, fermentation, rinsing, drying, hulling, and grading. This method is favoured for producing clean, high-acid coffees.

How long does coffee fermentation take in wet processing?

Coffee fermentation in wet processing takes 24 to 36 hours. During this time, the sticky mucilage is broken down enzymatically. The water must be changed every 12 hours to prevent contamination and ensure even fermentation.

How are coffee cherries sorted before processing?

Coffee cherries are sorted by hand or using water tanks and screens to remove unripe (green), overripe (dry), damaged, and defective cherries, as well as leaves and twigs. Only fully ripe, red cherries proceed to the next stage of processing.

How long does it take to dry coffee beans after washing?

After washing, coffee beans are dried for 5 to 7 days if sun-dried on concrete patios or bamboo mats. They must be turned regularly and protected from rain. Mechanical drying can shorten this time but is less commonly used in traditional smallholder setups.

What happens after the coffee beans are dried?

Once dried, the beans are hulled to remove the parchment layer, then hand-sorted to remove defects. They are graded by size and density before being packaged as green coffee ready for roasting or export.

Recommended FrontStreet Beans for Exploring Yunnan Small Coffee

Try FrontStreet Coffee’s Yunnan Arabica, a washed Yunnan Typica processed at medium roast with soft nutty and chocolatey tones, along with a gentle plum-like acidity. For a deeper dive, their 2013 Typica is a sun-dried classic with balanced sweetness, deep berry notes, and a tea-like finish. Both beans highlight the unique character of Yunnan’s small coffee cherries. Freshly roasted within 5 days · Orders placed before 17:00 ship the same day · Next-day delivery across most of Guangdong Province.