Grade Analysis of Ethiopian Coffee Bean by Solar method (High-shelf Solar method)

Ethiopian beans are easily recognizable. Most of the beans are small and pointed long beans, the so-called 'longberry', and often mixed with small oval-shaped short beans, the so-called' shortberry', looks uneven in size and uneven in appearance. The commercial bulk beans of Grade4 or Grade5 are mostly mixed with hundreds of different crystal seeds in different producing areas, so the phenomenon of uneven phase of beans is the most obvious, and it is not easy to bake evenly.

Ethiopian coffee beans are divided into five levels. The first and second stages are washed beans. Washed beans Grade1 represents 3 defective beans per 300g raw beans, and Grade2 represents 4 defective beans per 300g. Gradc1 grade water washed beans are very rare and are generally difficult to buy. At present, all the washed beans exported from Ethiopia are Grade2 grade. The quality of sun-dried beans is in the order of Grade3, Grade4 or Grade5. Although the defective beans in Grade4 are much less than those in Grade5, coffee farmers claim that in order to save tax on exports, they often lower the quality of Grade4 by one level to Grade5.

Coffee originated in Ethiopia in Africa, and then moved to Yemen in the Arab region of the Middle East, so some people call it "Arabica". Then it spread to Java, Indonesia, and from there to Latin America.

The sun treatment has a very high requirement on the climate, and if you encounter a rainy day in the sun, it will make the beans moist and moldy. When drying raw beans in the sun, the color is yellow, and the center will be brown after baking, rather than the white of washed beans. Sun beans have relatively better sweetness and mellow thickness, while less sour taste, but the quality is more unstable, there will be greater fluctuations. Due to the low cost of sun treatment, it is widely used not only in Ethiopia and Yemen, but also in Roboste coffee grown in Africa and Indonesia.

Sun treatment will first identify sunken beans in the sink, that is, ripe or half-ripe beans are spread in the drying farm for natural drying. The specific time depends on the local climatic conditions, which usually takes two to four weeks. When the moisture of the coffee bean is reduced to 12%, then use the sheller to grind off the hard pulp and silver skin.