Hulling
Wet and dry methods
Drying coffee beans naturally
After harvesting, if the coffee cherries were gathered by stripping or mechanical methods, the cherries are separated from any foreign bodies, stones, twigs and leaves. Then, the coffee seeds are extracted from the cherries by one of two methods: “wet process”, where the fruit is pulped, the hull is removed and the seeds are then dried, and the “dry process” where the whole fruit is dried.
The Wet Process
The wet process is longer and more complex and used primarily for cherries that have been picked by hand. Immediately after gathering, the fruit is passed through special pulping machines that free the beans, still wrapped in their parchment, from the cherries. The pulping is followed by two or three days of soaking in large water tanks where the beans are “washed” to completely remove the pulp through fermentation. Additionally, the fermentation triggers a series of chemical reactions that enhances the flavor quality of the roasted coffee. After fermentation the beans are sun-dried and the outer parchment is removed. The net result of both the wet and the dry processes is fruit that has been transformed into green coffee.
The Dry Process
The dry process is usually used for coffee cherries that have been harvested mechanically or by manual stripping. The cherries are spread out on threshing floors and left to dry in the sun for up to twenty days. Then hulling machines are used to free the beans from the hull and parchment once the skin, flesh and seeds have completely dried. The dry method produces “unwashed” coffees.
Sieving
The last step is sieving where the beans are separated from any impurities and graded according to shape and size. Generally speaking, the larger the beans, the higher the price. Green coffee beans are typically packed in 60 kilogram jute bags and marked with an identification card, ready to be shipped from the producing countries to roasting facilities around the world.