Coffee is processed by two widely-known methods – dry and wet. Ethiopia exports 80-85 per cent natural or sun-dried coffee and 15-20 per cent wet-processed coffee.
- Sun-Dried Coffee Harvesting: The time of flowering determines the time of the maturing of the coffee fruit. In coffee plantations, flowering does not usually occur all at one time. Usually there are two, three or sometimes four independent flowerings when successive rains occur. In most coffee-growing areas, the flowering period is between December and April and the harvesting period falls between August and January, i.e. seed maturity occurs mostly six to nine months after the blooming period triggered by rainfall. This ensures continuous production throughout the year. The coffee harvesting is done mostly by family labor, as the size of the average coffee farm is as small as 5 ha.
- Drying: Natural coffee is dried much more slowly than wet-processed coffee, because it is harvested with a variable moisture content that sometimes requires water to be removed from throughout the whole fruit. Natural coffee is dried in about three to four weeks in the sun, longer in cloudy or damp weather.
The coffee cherry is allowed to dry to about 11.5 per cent moisture in the whole fruit, after which all the outer layers are removed together by hulling and the commercial bean obtained and delivered to the central market.
- Hulling: After the dried cherries arrive at the hullery, they are cleaned and stoned before they enter the huller. Undersized cherries are separated for reprocessing. The basic raw materials required from successful hulling are fully-dried cherries of reasonable and even size.
- Wet-Processed Coffee: Since consumer preference is for wet-processed coffee, Ethiopia intends to increase the quantity of this commodity it produces. There are currently more than 400 coffee-washing plants in the country, owned by co-operatives, former state enterprises and private companies. At full capacity, these plants can produce about 52,000 tonnes of washed coffee per annum.
The country is well-known for its high-quality wet-processed coffee because there is a well-established and linked structure that connects coffee farmers, processing -plant owners, governmental organizations and coffee-purchasing enterprises, leading to effective quality control and efficient marketing.
The extension program, which includes experienced professionals at all levels, disseminates processing extension services to all producers. In particular, coffee harvesting and handling techniques are passed on by extension agents, and technical support is provided by professional processing experts at each plant.
Besides, each year, before the start of wet-processing operations, training is given to all operators engaged at each washing plant. Each specialized operator knows his duties and responsibilities well, and this is supported by strict supervision.
It is well-known that top-quality coffee is produced only from freshly picked, fully ripe cherries, and farmers are always advised to pick only these. Harvesting is done carefully, under close supervision. In addition, the cherries are sorted before pulping and unsuitable cherries are removed. The final sorted and clean cherries are pulped the same day they are harvested.
The pulped wet parchment coffee goes to the different fermentation tanks to ferment naturally. The process is carefully supervised to avoid under- or over-fermentation.
The fermented coffee is finally washed with clean running water and soaked in clean water to degrade and remove the remaining mucilage and acids and to improve the color of the beans. The wet parchment coffee is dried in the sun on raised drying tables and sorted at 11.5 per cent moisture.