Coffee Processing

After harvesting, coffee is then processed to remove the outer layers of the cherry and prepare it for sorting, grading, and export. Processing must begin immediately after harvesting.

There are 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 have 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.

Dry processing includes
a) Pre cleaner
b) Destoner
c) Huller / Peeler polisher
d) Catador
e) Cylindrical grader / Flat deck grader
f) Gravity separator
g) Color sorter
h) Storage tank

coffee dry processing layout

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 outer 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.

After plugging the cherry from the tree ( Red in colour)
a) Green bean separation --> green bean separator
b) Syphon tank --> Fabrication
c) Pulping --> Pulper
d) Fermentation ( civil tank construction)
e) Washing ---> Horizontal washer and Vertical washer
d) drying --> Dryer

Either way, the finished coffee is known as "parchment", referring to the final layer which remains on the beans.

coffee wet processing layout