WET HULL PROCESS
Two Indonesian workers are processing the coffee in a process known as “Wet Hull”.
We want to dive in more about the processing method behind our August drop - the Gayo Burni Telong - as the processing method is so unique and interesting. This method, also known as “Giling Basah”, is used by Mahdi Usati and other Indonesian producers. Wet Hulling is distinctive and characteristic of Indonesian coffee producers: Indonesia is the only country where they use this process.
So what is wet-hull processing? It’s a quick-paced drying method, necessary for the warm and balmy Indonesian climate. As a tropical country, Indonesia has hot, humid and rainy weather year-round, with humidity levels averaging around 82%, and the low only dropping to 75% in the dry season. For these reasons, keeping coffees dry for extended periods of time can be difficult for Indonesian coffee producers, so they’ve found a method that works with the climate rather than against. It’s also an economic alternative to other processing methods.
Sorting cherries
Coffee workers sort the Cherries by moisture content level, getting them ready for the wet hull process.
Wet hulling is similar to wet processing, with a few minor (but necessary!) differences and deviations in the drying methods. Here’s a breakdown of this unique and traditional Indonesian processing method:
Cherries are picked, and put through a hand-cranked machine, which removes the skin from the coffee cherries (depulping them, but leaving the mucilage layer on - the fruity layer under the skin).
The cherries are left overnight to ferment, and breakdown the fruity layer on the cherries: the mucilage, which is washed off afterwards.
The cherries are left to dry for only a few hours, until the moisture content is 50%. (This is where the big difference occurs, as other processing methods dry until the moisture content is down to 10-12%).
The coffee is taken to a mill, where it is further dried on patios until the moisture 25-35%. The wet huller machine removes the parchment - the outer layer still remaining on the coffee cherry - in addition to removing some of the water content.
Finally, the coffee is dried down to 12-13%, a much closer number to the original drying moisture content levels. The coffee dries very quickly at this stage.
You now have wet-hull processed coffee, ready for export.
The humidity levels in Indonesia make it hard to fully dry down the coffee with the parchment layer still intact. Wet hulling helps dry the coffees more efficiently, and also enables the producers to quickly sell and export the coffee, which is necessary due to the rate which coffee crops grow in Indonesia and are ready for picking.This process method emphasizes body over specific notes, but the Gayo Burni Telong still retains an earthiness and sweetness to it, with low acidity.
We hope you liked learning more in-depth about this unique coffee process, and are able to taste the hard work of our producer partner Mahdi Usati, and the full and rich body of the Gayo Burni Telong.
Enjoy!
Wet hull process
Wet huller machine, which removes the parchment - the last layer removed before the final drying time.
