Coffee Processing in Review

There’s been a lot of work going on lately in coffee growing areas with coffee processing. It’s been a very neglected area of coffee for a very long time and it’s interesting to see some new and innovative techniques being brought into this area. 

More than just Washed and Natural Process

If you’ve been to one of our coffee brewing classes, you’re familiar with the difference between a washed process coffee and a natural process coffee. Those are two of the most common coffee processing methods today. However, there are other methods as well that fall somewhere in between those methods. If all of this is confusing you, here’s a brief overview of the different methods of coffee processing for you to catch up: 

Washed Process Coffee

When the farmer takes the coffee cherry to the mill, often times, the first thing they need to do is remove the pulp and sugary outer layer of the cherry from the seed on the inside. One way is to run the coffee cherry through a machine called a depulper which removes the outer part of the cherry. Then, the depulped seeds are allowed to sit in a tank of water to ferment and break down the sugars still on the seed before they are washed with water. 

Washed process coffees tend to have a very “clean” cup profile. All of the mucilage and pulp of the cherry is washed off of the bean and then it is allowed to dry on patios or raised beds. 

Coffee Beans in Fermentation Tanks

Natural Process Coffee

The opposite end of the spectrum is a natural process coffee. These coffees are allowed to dry in the sun with the pulp and skin on the seed the entire time. In doing this, the sugars in the cherry remain on the seed the entire time. Some people say you get a more flavorful, sweeter note from a natural process coffee. On certain coffees, like a natural process Ethiopian coffee, you get a lot of fruity notes in the cup. This is what naturals are known for – bright, fruity flavors. 

Natural Process Coffee on Drying Beds

Honey Process Coffee

One of the newer processing methods in coffee is called a honey process. In this process, a portion of the pulp and mucilage is removed from the cherry, but some of it is left behind. They leave this out to dry just like in a natural process coffee. 

There are different kinds of honey process coffees. they are generally referred to as black honey, red honey or yellow honey. All this has to do with is the amount of pulp that is left on the coffee seed while it dries. A yellow honey has very little left and is closer to a washed process coffee. On the other end, a black honey has most of the pulp and mucilage left on the seed and is closer to a natural process coffee. 

What about Fermentation? 

Very interesting question. Fermentation is a step in coffee processing where coffee is left in tanks so the sugary pulp and mucilage breaks down. It’s an important step and, until recently, not much research has been done into this. However, there are some interesting steps being taken to improve this step and evaluate how fermentation affects the flavor of the coffee. Some people with backgrounds in wine making and other areas are working with coffee growers to help improve and better quantify how fermentation affects coffee. 

One interesting process that we’ve been able to taste in our latest coffee sample box is Anaerobic fermentation. The folks over at Genuine Origin and Volcafe worked with some processing mills in Costa Rica. Instead of leaving the coffee out in open vats, they put it in hermetically sealed stainless steel tanks. They were able to better control the rate of fermentation as well as the environment that the coffee was in. The result, if you’ve tasted the samples, is quite amazing.