Coffee is an important cash crop in many parts of Africa, Asia and Latin America. For many of the African coffee producing countries, coffee is the main export commodity, mainly produced by smallholder farmers.
The two common and commercially important varieties of coffee are Arabica and Robusta, with the former being native to Ethiopia. Arabica, unlike Robusta, has a refined flavor, contains less caffeine, is less yielding and has weak resistance to disease and poor climatic conditions. It grows well in sub-tropical and equatorial regions at altitudinal ranges of 550-1100 m, whereas Robusta generally grows at altitudes from 1100-2000 m above sea level.
Coffee cherries are processed following the dry or the wet method. Pulp, parchment and waste water (mucilage) are by-products from the wet method and husks from the dry method. Both methods generate huge amounts of by-products to the hosting environment (as a mulch and fuel) with no or only very little use.
However, there are proven biomass conversion technologies that could also be applicable to the coffee by-products. Bio-chemical (biogas), thermal (charcoal), mechanical (briquetting), and fermentation (ethanol) are some of the technologies. There are promising results both from previous and ongoing research activities on coffee by-products. The challenges to implement the technologies could be financial constraints, lack of trained expertise in the field, and lack of awareness about the available conversion technologies.
text: Bilhate Chala