Traditional Sumatran coffees are wet-hulled. It's also called semi-washed coffee which may or may not be accurate since there are variations in methods. But wet-hulled is more exact, for these types of coffee are stripped out of the protective parchment layer when the coffee seed measures 25-50% moisture content. (Wet-process coffees are hulled when the coffee is rested for weeks-to-months and at 11% moisture or thereabouts). When the coffee has so much moisture, it is fragile. It is not the dense hard dry bean we know of as exportable green coffee, it can be torn in two between your fingers. So inevitably wet hulling damages a lot of the coffee in the process. Then the unprotected green bean is laid out to dry on patios where it can be further damaged. Sumatra coffee goes through a lot. It is prepared by hand before export, but the level of prep and just how many of these defects you can cull out on a conveyor belt depends greatly. Here is damage I found in a reject sample, showing a lot of physical damage, mold and other signs of re-wetting on the patios, Coffee Berry Borer (Hypothenemus hampei) insect damage, and nutritional problems at the coffee shrub. It's a smorgasbord. Enjoy! -Tom