Sumatra coffee from Indonesia has one of the most distinct characters of all origin coffees. Most coffee experts believe that its deep, pungent, earthy character results less from the botanical variety of the beans or the area where it is grown than from the unusual method of processing. Most coffees are either dry processed or wet processed, but Sumatra coffee is almost always processed by a method in between the two extremes.
In wet processing, the pulp is removed from the coffee cherry before the beans are dried. In dry processing, the seeds are dried inside the fruit before the skin, pulp, parchment, and a white film called silverskin are removed. Sumatra coffee, which is almost entirely grown by small farms, takes a middle way. The pulp is removed at the farm, but the parchment and silverskin are left on. The coffee is then dried in stages before the remaining layers are removed.
Varieties of Sumatra coffee
The four most common varieties of Sumatra coffee are Mandheling, Iskandar, Lintong, and Mayo. Mandheling has low acidity and a bold, earthy flavor. Iskandar has a slightly lighter body and less earthy, more refined flavor, with some sweetness. Lintong has a deep, complex flavor with a lot of smokiness, and Mayo has a heavy, almost syrupy body and intense earthiness.
There is also a variety known as Kopi Luak, which is made from the coffee beans excreted by a variety of civet called the luak after it has eaten the fruit. Kopi Luak producers either “harvest” the beans from the feces of wild luaks, or keep luaks in cages where they are fed on coffee cherries. Since this is obviously a labor-intensive procedure, Kopi Luak is the by far the highest-priced coffee in the world, going for about $300 a pound, roasted. They say the smell of roasting Kopi Luak is not to be believed, which is probably another reason why most roasters don’t offer it.