The Technology of Coffee: the Processing Plant

In Costa Rica, 130 coffee milling plants can be found for the coffee berry. A well qualified labor force helps to make a consistent quality of coffee beans possible.

Although the blossoming and ripening processes are not uniform with all types of coffee, the normal collection of the coffee cherry is impacted due to the berry’s own enzymes which cause a rapid fermentation process. Thus, it is imperative to transport the cherry as quickly as possible to the milling plant, within a period of time that should not exceed 24 hours. This can be verified in the guidelines and training that the processing plants personnel receives annually.

The milling plant carries out a volumetric measurement of the fruit in double hectoliters (0.2 m³), the official measurement in Costa Rica. The quality of this measurement is supervised by the ICAFE personnel. To work in parallel with this, some plants have also implemented an automated system that verifies the volumetric measurements and weight of the coffee, thus facilitating their control over the process.

The depulping is done under the strictest of care, checking the water consumption (and its recirculation) and utilizing equipment with controls and settings that ensure the least amount of damage to the bean. This is achieved through constant evaluations made during the harvesting period. 

The pulp is mechanically removed from the milling plant in order to reduce the possibility of contamination through the use of water. Helical transporters or conveyor belts are utilized.  The by-product is currently being developed for use as organic fertilizers and fuel, among other possibilities. 

The removal of mucilage, necessary for drying the seed, is done mechanically and/or through natural fermentation. Utilizing strict controls for water usage, each processing plant is equipped with a water treatment system, ensuring that the country’s strict environmental laws are met.

Some of the milling plants use a water treatment system for the production of bio-gas, useful in the drying of the coffee.  The wet processing system, used for our Arabica coffees, preserves the quality that has been developed in the field. Although this is a costly method, it has proven to be the most effective for the milling of select Costa Rican coffees.

In the drying process, natural and mechanical methods are used along with temperature and humidity controls, fundamental in obtaining high grade quality coffee. Some of the milling plants, looking to optimize the drying process and the use of natural resources, have begun to monitor the flow of incoming air into the dryers, the electrical consumption and its by-products, and the usage of solar power.

Once the parchment coffee has reached an average humidity level of 12%, the coffee is stored under strict conditions in silos or warehouses until it has been sold. 

When the coffee has finally been hulled (the parchment is removed), it is transferred to a machine that cleans off the impurities. Next, the coffee bean is sometimes classified according to color, size and density. The coffee is packaged or placed into containers, either for exportation or to be roasted for local consumption. However, it maintains the special characteristics that have been acquired from its unique place of origin in one of the coffee growing areas of the country.