“Processing” refers to the method by which the fruit, or “cherry,” is removed from the coffee seed after it has been picked at origin and well before it arrives at our roastery. The different ways coffees are processed directly impacts how the coffees will taste in the cup. There are many variations in the way coffees are processed due to factors such as availability of water, equipment, regional tradition, transportation requirements, and weather patterns.
Of all the methods, the washed process removes the most fruit. The coffee cherry is pushed through a pulper, which removes most of the fruit and expels the bean. To remove what fruit is left on the seed, the coffee is allowed to sit in a moisture bath for 12-36 hours. The sugars present in the fruit cause a basic fermentation process to take place, which loosens the fruit. The loosened fruit is then washed away, leaving a clean coffee seed that is ready to be dried. The moisture bath allows the coffee to osmotically equalize in sugar and moisture content. This makes consistent roasting easier and is one of the reasons why washed coffees are often preferred by coffee roasters.
Countless variations of this process impact the final cup profile. While washed coffees display an incredibly wide range of flavor profiles, they all tend to be clean with higher levels of perceived acidity.
“Honey processed” and “pulped natural” are other names used to describe the semi-washed process. Like a washed process coffee, a semi-washed coffee is run through a pulper, and most of the fruit is removed, but unlike a washed process coffee, a semi-washed coffee is not placed in a moisture bath. This means that some of the residual fruit that was not removed by the pulper remains on the seed. This residual fruit is dried along with the seed, often resulting in a coffee with complex fruit notes and sweetness.
A coffee cherry that is dried with the fruit and skin intact is referred to as “natural processed” or “full natural”. The coffee cherry is picked from the tree and placed directly on drying beds or a cement patio. The fruit isn’t removed from the seed until it has been fully dried. Moisture activity between the seed and drying fruit, along with some natural fermentation, produces huge fruit flavors. These big fruit flavors make a natural processed coffee easy to identify in the cup.
The lack of a moisture bath during processing results in a roasted coffee with lots of color variation due to fluctuating levels of sugar content. The variations that arise from naturally processed coffees create many challenges when it comes to roasting. These challenges often prevent large roasters from buying naturally processed coffees. We believe, however, that these challenges are worth overcoming. We’re proud to offer some naturally processed coffees that are unique and exciting.
Drying & Milling
After coffee seeds have gone through one of the above processing methods, they must be dried. The seeds are placed on cement patios, raised beds, solar drying beds, or mechanical dryers, and are dried until their moisture content is reduced to about 10-12%. Drying the seeds should leave them in a dormant state without killing them.
Once dried, the coffee is delivered to a dry mill in preparation for export. At the dry mill the coffee is sorted by size, density, and color, and any defective seeds are removed. This last stage of processing is the final quality check before the coffee arrives at our warehouse in Portland, Oregon. For this reason, the dry mill plays a massive role in ensuring that our green coffee is of the highest quality when we get it.