The Processing of Coffee

At origin, specialty coffee is carefully grown, harvested, and meticulously sorted. After being sorted the coffee must be properly processed. Below, we’ll learn more about the four main processing methods of coffee, how each method is used, and what makes it unique. But before we begin, let's start with the anatomy of the coffee cherry. Like any fruit, the coffee cherry has layers, and these definitive layers help create a foundation for each processing method. In the simplest terms, the layers are: the skin, the mucilage (fruit), the parchment (thick cellulose layer), the silver skin (chaff), and the seed.

New processes are always being invented (especially recently!) but most of these are variations on the following main processes: Washed, Semi-Washed, Natural (or Dry), and Honey Process. Each processing method can be used to produce an excellent cup of coffee but location, resources, and the skill set of the processor is what differentiates them.

The most common of all is the Wet or Washed Process. The Washed Process is when the coffee's cherry is mechanically stripped off of the seed (called Pulping) while leaving the mucilage (pulp) on the parchment. The seed is then placed again in water to naturally ferment the coffee and remove the remaining mucilage that surrounds the coffee's seed. This process is very popular in water rich countries such as Central and South America. It is also known to give the coffee clear and transparent tasting notes. This coffee process can create an excellent cup, although some theorize that the process literally washes off some the natural flavors of the coffee.

Next is the Wet Hulled/Semi-Washed Process. This process is a subset of the Washed Process which begins with the cherries being pulped, washed with their mucilage still intact, and then set out to dry/rest for twenty-four hours. After a full day of rest the beans are washed again to remove the mucilage and set out to dry until it reaches a certain moisture content. The Semi-Washed Process is used mostly in Indonesian countries and has a reputation to have more earthy tasting notes due to its exposure to the elements, second washing, and often uneven drying. While some people love the earthiness, others find the cup muddled and lacking acidity.

The Natural or Dry Process is in some ways the opposite of the Washed/Semi-Washed Process. The Natural Process is when the coffee bean is dried in cherry form by being placed in sunlight on patios or raised beds to dry. The seed remains in its fruit until the dried cherry can easily be removed. This process can take weeks to complete. During that time the seed is soaking in the sugars of its cherry, and can produce a wildly rich and flavorful coffee. Natural Processing is used mostly in Brazil, Yemen, and African countries. This process is simple in its execution and is perfect for countries with a limited resource of water. Some customers love the added notes of fermenting fruit (especially in the aroma), while others dislike the characteristic funkiness and find the cup to lack clarity.

The Honey or Pulped Natural Process is when a coffee cherry’s skin is removed and all or some of the pulp remains. The skinned cherry is then dried in a fashion similar to the Natural Process. While the seed is drying, the pulp takes on a honey like texture and color, thus the name of the process. This method was invented by the Brazilians, but was adopted by many farmers around the world. The Honey Process can also be broken down into other subgroups. Processors have learned adjust the amount of the pulp that is left on each bean, and the amount of sunlight required to dry them. Each subgroup is given a name by the percentage of pulp left on the bean. The first is the Yellow Honey process which has 25-50% of pulp left on the seed and is turned hourly to ensure it is consistently dried. The second is the Red Honey process which has 50-75% and is turned multiple times a day but less than the Yellow Honey. Finally, there is the Black Honey which has 75-100% pulp left on the parchment and is only turned once a day.