Milling and Grading

The final step takes place in the factory. The parchment is “hulled”, that means the silver skin (parchment) is taken off the green bean. The beans are transferred to a combined machinery where the hulled beans pass over a gravity table and enter into screens which separate the different sizes of beans (“grading”) according to grade or screen. The largest beans are called grade AA or screen 17, followed by A, AB and B. Size is not equivalent with quality and specialty coffee can have a mix of 60% AA, 30% A and 10% AB. After hulling, the green beans are yet again sorted, by hand as well as by a digitalized scanning machine, the “color sorter”. Thereby the last defects are eliminated.