Impact of Sun Drying Methods and Layer Thickness on the Quality of Highland Arabica Coffee Varieties at Limmu, Southwestern Ethiopia

Abstract

Coffee is the most important crop in the national economy of Ethiopia and continues to be still the leading export commodity. Despite the economic importance, productivity and quality of the crop is very low. Improper post-harvest processing techniques largely contribute to the decline in coffee quality. However, lack of information on the effects of post-harvest processing and drying on quality necessitates a comprehensive study. Therefore, this experiment was carried out to determine the effects of sun drying methods, variety and cherry drying layer thickness on quality of coffee at highland areas of Limmu, Jimma zone. Accordingly, on-farm processing experiments were conducted at state owned coffee farms under Limmu Coffee Plantation Development Enterprise (LCPDE) from September up to December, 2010. The experiment was laid out in 3 × 3 × 4 Split-Split-plot design arranged in CRD with three replications. The three factors comprise three drying materials: bricks floor, raised beds with bamboo mats and mesh wires assigned to the main-plots. Three coffee varieties: 744, 74110 and 744+74110 assigned to sub-plots and four levels of cherry layer thicknesses: 20; 30; 40 kg/m 2 (uniformly spread) and the farmers' conventional practices (40 kg/m 2 ) as sub-sub plot treatments. The data were computed by using list significant differences (LSD) procedures of SAS version 9.2. As a result, the interaction effects were highly significant (P ≤ 0.01) for total coffee quality and significant variations were observed (P ≤ 0.05) for drying period, total raw quality, total cup quality and coffee grades. The finding revealed that; processing coffee on raised beds using appropriate layer thickness loads of 20 to 40 kg/m 2 at high altitudes produce quality coffee identified as total quality scores ranging 80-89.99 points and can attain "Specialty Grade 1 and 2" classification profiled under grade 2. While, the conventional systems produce low quality coffee identified as commercial grade classifications profiled under grade 3 to 4. Hence, using appropriate dry processing approaches, it is possible to produce specialty coffee.

Performance Analysis of Flat-Plate and V-groove Solar Air Heater Through CFD Simulation

“…In most rural areas of Ethiopia, Open-air sun drying and outdoor terraces are still common among coffee producers. Among total coffee product of Ethiopia, washed coffee represents 29% while sun-dried coffee represents 71% of the total (Musebe et al, 2014;Ali Mohammed, 2014). In the country's economy, around 15 million people depend on coffee production for their livelihood and around 60% of foreign income comes from coffee.…”