The Lab

Post Harvest Coffee Processing: Wet Hulled

The wet-hulled process is primarily found in Indonesia and the surrounding islands. The process evolved to dramatically decrease the drying time of the coffee because of the regions heavy and consistent rainfall. The farms here are small (<1 hectare), and it is where processing typically starts. The supply stream is fragmented and the coffee may be bought and sold several times before reaching the port of export.

Lake overlook in Bali

Coffee is handpicked by the farmers and sometimes floated in water tanks to remove any underdeveloped or damaged cherries. It is then pulped using small, wooden hand-operated machines. In some instances the coffee is sold as whole cherry or as pulped mucilage. More often, it is fermented overnight to breakdown the mucilage layer. This may be a wet fermentation which involves soaking the coffee overnight in small buckets. Or it will be dry fermented which is when the pulped mucilage-covered coffee is packed in bags overnight. Wet-fermentation generally produces a higher quality coffee. The next day it is laid out to dry, only for a few hours, on patios, rooftops, or sometimes inside the home on the floor.

This initial drying will stop when the coffee is between 40-50% moisture. It is bagged and sold to a collector who will transport and sell the coffee to a more centralized mill. The mills have relatively expensive and specialized equipment which can remove the parchment layer while the coffee is still relatively wet. Removing the parchment decreases the drying time from several weeks to 1-2 days.

Drying Patio in Java

The parchment layer protects the seed from the environment, and when this layer is removed, the seed is vulnerable. The coffee’s final flavor will be indicative of how it is handled in this stage. If the facility and equipment is not clean and dry, the flavors will be less refined.

Wet hulled coffee has a characteristic earthy and heavy bodied flavor profile. The flavors may be more muddy and defective if there is not great care taken in how the coffee is transported and dried. The flavor profile is clearly recognizable and desired by many. Royal NY sources a variety of wet hulled coffees from Indonesia, for more information about our offerings, contact a trader.

Patrick McKeown

Patrick began his coffee journey on Long Island at a small coffee bar and roasting at home. Since then he has been a barista, manager, and craft roaster in NYC.