No abstract

Solar tunnel drying and semiwash processing methods are popular among coffee growers in southwestern Ethiopia. However, the effect of these processing methods on coffee quality has not been studied in detail. The objective of this study was to evaluate the effect of processing and drying methods on the quality of coffee varieties at Gomma-I and Limmu Kossa areas in the 2016/2017 growing season. Two processing methods (fully washed and semiwashed) and three drying methods (solar tunnel, artificial, and natural sun) were compared using three coffee varieties (741, 7440, and 74110) to test their effect on coffee quality. Coffee beans processed by semiwash method and dried by solar tunnel produced nondefective (primary and secondary) coffee beans compared with others at both locations. Similarly, coffee beans processed by semiwashed method recorded the highest mean value for shape and make and body than wet processing method. Best coffee bean color, greenish color, was produced from coffee beans processed by the fully washed processing method. All coffee varieties processed by semiwashed method produced medium pointed acidity, the second most acceptable grade value for coffee quality for all drying methods. Coffee beans processed by the fully washed method produced more flavor than semiwash processing method. Coffee beans dried by sun and solar tunnel drying methods also produced better flavor than artificial drier. In general, all coffee varieties processed by semiwash method and dried by natural sun and solar tunnel method produced higher preliminary total quality and total specialty coffee value, graded under specialty grade Q1. Hence, coffee growers in the study area can use semiwash processing method and solar tunnel dryer as an alternative/complementary processing method since they produce better or equivalent quality product with full wash and natural sun drying method.

Around 40% of coffee quality is determined in the field, with the remaining 60% determined by post-harvest processing procedures. This demonstrates the significance of coffee processing in improving quality and value. As a result, this article examines the economic viability of Horizon Coffee Plantation Farm's three coffee drying methods: solar tunnel dryer, artificial dryer, and sun dryer. Several economic viability assessments and cost-benefit analyses are used. Furthermore, for each strategy, switching values and sensitivity analysis were done. According to the findings, the gross margin rate for the solar tunnel is Birr 35 per kg of green, followed by Birr 34.75 for the artificial drier machine and Birr 34.2 for the sun dryer method. Similarly, the artificial dryer method was found to be the most viable, with the highest NPV of Birr 89,292,673, followed by Birr 10,016,909 for the solar tunnel method and Birr 175,295 for the sun dryer method, implying that the firm's methods are all economically viable. The BCR and IRR criteria also confirm the same conclusion. The viability of all drying methods remains nearly constant regardless of the potential in costs of production and sales prices. Because investments in all drying methods are non-mutually exclusive, it is advised that the corporation continue to invest in all three drying methods as long as their NPV is greater than zero. However, this finding should be interpreted with caution because the present rise in fuel prices may make the use of artificial dryer methods more expensive and unviable.