After harvesting coffee is then processed to remove the out layers of the cherry and prepare it for sorting, grading, and export. Processing must begin immediately after harvesting.
There is two ways coffee is processed after harvesting, the Dry Method and Wet Method.
The Dry Method
Also called Natural Process, this is the traditional way of processing coffee. The harvested cherries are spread over a concrete or brick patio, in full sunlight, and raked at regular intervals to prevent the beans from fermenting. If it rains or temperature drops, the beans are covered to protect them. After 7 to 10 days, when moisture levels within the cherries has fallen to 11%, the cherries are considered dry. The outer shell will have dried to a dark brown and become brittle. The dried cherries are then stored in silos.
The Wet Method
This method requires greater investment and more care than the dry method. The main difference between the two methods is that the wet method uses a pulping machine to remove the outer layers of the cherries from the beans within. This is done within 24 hours of harvesting. Cherries are carried by water, hence "wet method", and washed through the pulping machine which squeezes the beans from the cherry pulp, the beans are then carried through washing channels which separates the lighter, immature beans from the heavier, mature ones. The beans are then stored in fermentation tanks for 12 to 48 hours during which time enzymes work to naturally separate the remaining out layer from the parchment covering ( the endocarp ). When the process is complete, the beans must then be dried to 11% moisture content. The beans will be dried either by sun on patios or by mechanical dryers.
Either way, the finished coffee is known as "parchment", referring to the final layer which remains on the beans.
Wet Method coffee tends to have more acidity in the cup with a thinner body. Coffee process through the Dry Method will have a heavier body with not as sharp acidity. Most countries produce either wet or dry coffee, however a few do use both methods.
Wet Method Origins
Colombian, Java, Kenya, Mexican, Costa Rican, Guatemala, Hawaii, Jamaica, Nicaragua, Zimbabwe, Tanzania, and many more.
Dry Method Origins
Sumatra & Celebes, Origins Offering Both Methods, Brazil & Ethiopia
Coffee is next sorted by size and defects are removed. The size of coffee beans is expressed by a Screen number. Coffee bean are passed over metal screens which are punched with holes. The first screen has holes 18/64 ths of an inch, beans smaller than that fall through the screen. The next screen has holes 17/64 ths of an inch, below that they are 16/64 ths of an inch, and so on. Beans are separated out by size and classified by the number of the screen they sort at. Our Colombian Supremo is always Screen 18+ which means all of the beans are 18/64 ths of an inch or larger. While we can purchase Colombian Supremo with a Screen of 16 , 17, or 17/18 mix, we require Screen 18+ to insure we have the best possible coffee.
Defects in coffee can be broken beans, black beans, pits of wigs or branches, or any foreign objects which make their way through processing and hulling. Defects are removed several ways depending to the technological investment at any given mill. Traditionally defects have been removed by hand. Coffee passes in front of rows of sorters on conveyors. as the coffee passes by, defects are picked out. Some of the more advanced coffee farms, such as those on the Hawaiian island of Kauai, use color monitoring eyes that activate a blast of air to shoot bad beans out as they pass in front of the eye.
The final grade of coffee is determined by a random sample take for a given lot of beans. The number of defects within that sample will determine the grade of the whole lot. The more time and care given by sorters the higher the grade will be since more defects will be removed.