Processing refers to the method of taking a coffee cherry and turning it into a dry green coffee bean. This has two steps: wet milling and dry milling. Wet milling is how a coffee seed, or bean, is removed from the fruit and dried for storage. There are three different ways this is done.
In the washed process, the cherry’s skin and flesh are stripped off using a mechanical depulper, but a sticky layer of fruit called mucilage remains. This remaining fruit is first loosened by soaking in a fermentation tank, then rinsed off. The coffee is then dried so it can be stored until it’s time to roast. These coffees are known for their crispness and balance. We serve these the most at Clarity.
The second process is called dry, natural, or as we like to call it, sun-dried. In sun-dried coffees, the cherries are spread out on a patio or drying table first, with the fruit intact. For several days, they dry just like any other fruit would in the sun - think raisins. Then the fruit is removed mechanically, and the new green coffee is stored. Sun-dried coffees are known to have intense fruity flavors.
Semi-washed, wet-hulled, pulped natural, honey: these “hybrid” processes go by a lot of names, and they do have a few distinct differences, but they have even more in common. In these processes, the coffee is run through a depulper and then immediately dried with a small amount of fruit left on the seed. This allows the coffee to take on some of the sweetness of the fruit without the risks of rot that come with sun-dried coffees.
After wet milling, the coffee is stored in pergamino. This little natural parchment around the bean protects it from the elements and keeps it tasting fresh. Right before it is ready for shipment, it will be removed, usually mechanically. The removal of this parchment is called dry milling. Once the coffee has been dry milled, it can be bagged up and shipped.
Check out the section on Roasting to see how to turn the coffee from green to brown.
All photos on this page courtesy of Cafe Imports.