Wet-Processed for Quality and Flavor
The processing of coffee cherries by highly-skilled and trained farmers is a critical step that sets apart a spectacular final product from a marginal one. Once coffee cherries are harvested, the pulp must be removed from the coffee cherry to extract the coffee bean. Farmers can either wet-process or dry-process the coffee cherries. In Nepal, most coffee growers wet process their harvest within 24 hours of picking.
With wet processing, freshly harvested cherries are again hand-sorted and placed into large basins of water. Naturally, the good cherries, being denser, sink to the bottom and the unripe or defective cherries float to the top. Once the unwanted cherries are removed, a wet-pulping device removes the outermost layers of the fresh cherry without damaging the coffee bean.
After the pulp is removed, the coffee beans are placed in fermentation tanks for 24-48 hours to fully remove the remaining pulp residue. Once fermentation is complete, the beans are then thoroughly hand-washed and sun-dried for four to five days. This drying process causes the papery, protective shell (called parchment) surrounding the bean to become crumbly, making it easier to remove during the hulling stage of production. Because of Nepal’s cooler climate and variable weather conditions, it generally takes coffee beans longer to ferment and to dry than in other coffee producing countries. Coffee greens are then stored parchment-intact to maintain freshness.
Farmers in Nepal often save the scraps from this pulping process for composting. This material gives nutrients back to the plants and protects them from root infestations.
The alternative processing method is dry processing the coffee cherries, where the cherries are thoroughly dried for weeks before the pulp is removed. However, specialty coffee producers worldwide generally prefer wet processing as it leads to a higher quality, more flavorful coffee. Wet processed coffees are known for their clean, bright and complex flavors, whereas, dry processed coffee is sweeter and fruity. The wet process method allows specialty growers to have more control over production, influencing the final flavor of the bean. Growers can make decisions during the fermentation process to influence and bring out the flavors of the coffee bean.
Some research courtesy of The Perfect Daily Grind, Plantec Coffee Estate.