What Makes Mandheling Coffee Unique? The Giling-Basah Process!
Mandheling coffee beans grow on the enormous equatorial island of Sumatra, part of Indonesia. Things evolve differently on Sumatra and Mandheling coffee is a good example. It owes its distinctive flavour and heavy body to a unique post-harvest technique known as Giling Basah, which translates literally to “wet hulling” or “wet grinding.” This process evolved not by design for its flavour, but as a practical necessity in Sumatra’s equatorial climate, characterized by high humidity and frequent rainfall, which makes traditional, slow-drying methods difficult.
The Giling Basah method differs massively from the globally common washed (wet) and natural (dry) processes. Especially in the timing of the coffee bean parchment removal. So let’s run through it: the process begins similarly to the wet method: coffee cherries are carefully hand-picked, then immediately run through a de-pulper to remove the outer skin. The beans, still covered in a sticky layer of mucilage and encased in a papery layer of parchment, are then fermented overnight. This natural fermentation breaks down the mucilage, which is typically washed off the following morning.
The critical divergence occurs during the drying stage. Instead of drying the parchment coffee for several weeks until it reaches the usual global standard of 10–12% moisture content, Sumatran farmers dry the beans for only a few hours, 24 at most, reducing the moisture content to a still high range of 30–35%. At this semi-wet state, the farmers sell the beans to the local mills.
At the mill, the coffee undergoes the “wet hulling” step: a specialized machine removes the still-wet parchment layer from the soft, water-swollen green bean. Removing the parchment while the bean is still damp allows the beans to dry much faster. Within just two or three days the beans will have reached the exportable 12% moisture level. This aggressive drying phase without the protection of the parchment layer is largely responsible for the coffee’s unique traits, including the signature bluish-green colour of the raw beans.
What this means is that the final cup profile resulting from the Giling Basah process is highly distinctive. It is characterized by an exceptionally full, syrupy body and notably low acidity. Coffee experts describe the flavours as earthy, herbal, and spicy, with hints of cedar, tobacco, or dark chocolate. They say Mandheling has a bold and rustic profile. We chose this coffee because it is so different. But what do you think? Try some of our delicious Mandheling coffee today and let us know if the experts are right?
