Natural processing is the original method used for coffee that consists of more hand labor than machinery.
There are higher risks of defects due to handling, drying, and hand-sorting. The coffee cherries are picked and then directly dried under the sun or on raised screens as full cherries (more then 6 weeks).
Once the cherry is dried, it turns into a dark brown pod that is hard to the touch; the green seed is taken out, leaving the other layers behind.
Because this process is so hands on and the defects can only visibly be accounted for, there is large room for error; greater chance of defects, taints, and a lack of uniformity in roasting in cupping occurrences.
While there is more room for error, natural processed coffees tend to have more body and lower acidity than their washed counterparts.
They are suitable for alternative preparation or single origin espresso, or are often used in espresso blends.