Processing refers to the methods used to transform harvested coffee fruit (aka coffee cherries) into the green coffee seeds (aka beans!) that we roast. It's one of many steps that coffee goes through before being brewed, and includes the steps used to remove the three layers surrounding a coffee bean (the cherry, mucilage and parchment), as well as how beans are dried. There are three main ways that coffee is processed, and each produces unique characteristics. They are natural, washed and semi-washed.
Natural Processing Creates a Heavier Body and an Explosion of Fruit Flavors
After the coffee cherries are harvested and sorted for quality and ripeness, they are immediately dried. Drying can take anywhere from 3 to 6 weeks. During this time, the cherry creates a closed environment, and its sugars ferment into alcohols that the bean soaks in. After the cherry is dried into a fruity leather, it is removed from the beans inside in a process known as "hulling", and the beans are prepared for shipping.
The sugars and alcohols from the cherry create the strong, fruit-forward flavors that natural processed beans are known for. Because this method leaves the beans inside the cherry, though, it produces inconsistent results. Therefore, although natural processed coffees can be excellent, they should be selected only after cupping and on a lot-by-lot basis.
Washed Processing Produces Clean and Bright Coffees
In washed processing, instead of leaving the bean inside the cherry, the bean is immediately removed from the cherry after harvest, in a process known as depulping. Many processors soak the beans in fermentation tanks, where naturally occurring microbes process the sugars found in the cherry. In Kenya, it's traditional to let the depulped coffee sit for up to 72 hours before going into tanks of water to be washed. This gives the beans additional time with the sugars on its surface, and leads to the super bright, berry and citrus flavors we're familiar with in Kenyan coffees.
After the cherry is removed, the beans are dried either under the sun or in mechanical dryers. Finally, the parchment is removed in a process called hulling, and the coffee is ready to be shipped.
By removing the cherry in the first step, washed processing produces more consistent coffees than natural processing does. Coffees that are washed are known for their bright, clean flavor profiles and lighter bodies.
Semi-Washed Processing Strikes a Balance
Semi-washed processing is also referred to as pulped-natural processing and honey processing, depending on the region. This method strikes a balance between dry and wet processing by removing the cherry, but not the mucilage, before the beans are dried.
All stages of processing are important, but drying requires special attention in semi-washed processing. The beans must be dried naturally, because the mucilage left on them would stick to mechanical dryer’s walls. As they sit under the sun, they must be constantly rotated so that the mucilage doesn’t collect in a single spot and cause the beans to rot. Once the beans are dried, they’re ready for shipping.
In this method, the mucilage dries into the beans, infusing them with flavors. These flavors are not as pronounced as the ones produced by the sugar6us and alcohols from both cherries and the mucilage in dry processing, though. Semi-washed coffees typically feature a balance of acidity and body, along with notes of sweetness that comes from the mucilage’s sugars.
Do You Like Natural, Washed or Semi-Washed?
Dry, washed and semi-washed processing all infuse coffee with unique characteristics. Natural processed coffees are known for their extra fruity flavors and big bodies. Washed coffees feature bright, clean and crisp profiles. Semi-washed coffees strike a balance between the two, with a rounded acidity, medium body and sweet notes.
As you explore new coffees, pay attention to how they were processed and keep track of which method produces the selections you like best. You can start by finding out whether your latest shipment from us was natural, washed or semi-washed here.