Coffee is one of the few fruits grown only for its seeds. But this presents coffee producers with a challenge, as the cherries must be processed– separated from the fruit, dried, and milled — before being exported. But processing is more than an obligatory step after harvesting: the methods the coffee producer uses has an enormous effect on flavor. In fact, many coffee professionals believe processing has a bigger effect on the way your coffee taste than the variety of the plant or the country of origin.
There are four main ways of processing coffee, with perhaps infinite variations within each category. Certain methods tend to be common in different regions, often driven by the local climate and available infrastructure.
Washed Process (Parchment-Dried)
For the specialty coffee world, the washed process (also referred to as parchment-dried) is the most common. With this method the cherries are first depulped by a special machine which range from small (pictured above), to the size of a warehouse. After the cherry is removed the seeds are fermented— often in a tank of water although some regions practice a dry fermentation in small piles— which allows yeast and bacteria to eat the remaining sugar on the outside of the seed. After fermentation the coffee is washed, often in channels, before being dried. Drying might occur on concrete patios, raised beds, or in large metal drums. After drying the coffee must be milled to remove a final, papery layer called parchment that encapsulates the coffee seed.
The washed process is the most consistent, as unripe “floaters” are easily separated. The final product tends to have a cleaner flavor profile and a more lively acidity. Coffee in Colombia, Kenya, and Central America is usually fully washed.