Coffee processing refers to the way that a seed is removed from a coffee cherry. Like any other pitted fruit, coffee cherries have a seed, the pulp, the mucilage around the seed, and a protective skin. There are various methods to remove the seed from that cherry, and these methods affect the seed's flavor as it gets roasted and turned into a coffee bean—this flavor sticks around till the final brew. There are four different ways to process coffee, all of which change the sweetness, body, and acidity of brewed coffee. These methods are called natural process, washed process, wet hulled, and honey processed.
Natural Processed Coffee
A natural processed coffee, also referred to as dry processed, is a traditional yet common way to process coffee today. Originating in Ethiopia, it involves drying out the entire freshly picked coffee cherry with the seed still inside. To do this, coffee producers take all of the cherries and place them on drying beds in the sun. These beds either consist of patios or raised drying tables. Throughout the course of 3-6 weeks, the coffees will ferment, as producers rake these cherries and rotate them to prevent spoiling. During this time, the sugars and mucilage (that sticky substance that coats the seed) will latch onto the seeds, which develop flavors and make them sweeter. Once the coffee is dry, a machine separates the pulp and the skin from the seed. Natural coffees, like our Hawaii Kona Extra Fancy, result in heavy bodied cups of coffee, with deeper and complex tasting notes due to that time spent developing extra flavors. This development comes from the way that the seeds ferment differently, since they dry with the full cherry still intact. Natural processed coffees can be difficult to replicate because of the inconsistencies in fermentation.
Washed Process
Unlike natural or dry processed coffees, washed processed coffees are called the opposite—wet processed! In this scenario, machines called depulpers remove the seeds from the cherries before drying them. However, it is not just any cherry that gets seed removal. These cherries must have the perfect amount of ripeness to make sure they are sweet enough, and go through a sorter for density. Once these depulpers remove the skin and pulp from the seeds, the seeds go into tanks full of water. The water ultimately washes the rest of the mucilage and fruit caked onto the seed. Finally, the seeds go onto beds in the sun to dry out. The washed method, although quick and efficient, can be considered environmentally wasteful. A massive amount of water goes into the tanks that remove the mucilage, and washing stations themselves generate tons of solid waste. These washing stations themselves take an incredible amount of infrastructure, technology, and energy that could be costly to many to operate. However, if the water in these tanks can be reused (typically by rebalancing. the pH level), then this processing method can work towards environmental friendliness.
Wet Hulled Coffees
Wet hulled coffee, not to be confused with washed/wet process, can also be called semi-washed coffee. During this processing method, depulping machines remove the seeds from the cherries. However, rather than move to drying beds, the cherries get stored in plastic tanks. The mucilage also remains on the seeds, and much moisture is retained. At this point, the mucilage has created a thick husk that encapsulates the seeds. They then go through a process called hulling to remove it, along with parchment (the dry flakes covering a bean) that surrounds the seeds, and laid out to dry afterwards. This method is common in Indonesia, for its humid climate can make the drying conditions difficult. Wet hulled allows for more efficient and speedy processing, as the drying time is half of the other processes. The taste of a wet hulled coffee, such as our Indonesia Sumatra, is also heavy bodied thanks to the dried mucilage, but it is also chocolatey, savory, and nutty—perfect for a blended roast. [Source]