The Horn of Africa Regional Environment Center and Network (HoA-REC&N) is an autonomous institution under Addis Ababa University. HoA-REC&N focuses on environmental concerns and sustainable development options within the Horn of Africa. Partner institutions include University of Hohenheim; University of Massachusetts–Boston; and the Oromia Coffee Farmers Cooperative Union.
Coffee accounts for 60 percent of the export earnings in Ethiopia, and is processed by dry and wet processing. Wet processed is preferred in the global market. Unfortunately, farmers do not see the full benefit of their coffee production. A significant portion of coffee harvested is of inferior quality due to the traditional sun drying process. This process can take up to twelve days and increases exposure of coffee to fungi and other undesirable elements. Thermal drying is energy intensive and takes up a large amount of space.
The proposed solution uses state of the art infrared technology to reduce coffee pulp drying time from several days to hours. Reduced drying time minimizes the post-harvest loss that occurs when using the conventional sun drying process. Biogas generated from coffee pulp and coffee husk will be used to power the bioreactors used for infrared drying.
The success of this project will lead to new opportunities that can transform the current traditional coffee production system while improving the quantity and quality of coffee by decreasing exposure of coffee to fungi and other undesirable elements. By reducing the time farmers spend in coffee processing, the time saved can be used for other productive uses which will help them generate additional income. The project will also improve work conditions for women and children, who are primarily responsible for the sun drying process which requires all-day exposure to the sun.
HoA-REC&N has been working on developing a biogas digester and an infrared (IR) dryer to dry coffee beans. Two potential suppliers have been identified for the IR dryer, with test drying conducted in early 2017. HoA-REC&N constructed and commissioned four bio digesters which were tested with two different coffee feedstocks–husk and pulp. The tests showed that the coffee pulp resulted in higher yields of bio-methane. Further experiments are to be conducted for the optimum yield. Additional experiments were conducted to analyze the effectiveness of coffee drying at different temperatures and power (these include thermal, microwave, and infrared).The results showed that the moisture level of coffee dried using infrared has decreased to the required amount. HoA-REC&N has identified two sites, including a large privately-owned coffee farm, to pilot their technology. Beneficiaries of the technology will include 8 coffee cooperatives, comprising 7,000 coffee farmers who will be able to sell a larger quantity of coffee due to reduced drying times. Future plans include the integration of the IR dryer and the bio digester units, following the optimization of the dryer.