This is arguably the oldest and most original form of coffee processing and was traditionally used to process cherries on a commercial scale due to the low costs involved (i.e in Brazil) or in areas with limited access to water resources (i.e Ethiopia).
After harvesting, the cherries are laid out to dry in the sun – on a commercial scale, they are usually laid on large concrete or brick patios though they are sometimes left directly on the earth to reduce the moisture content. It is for this reason that natural processed coffees will often throw up more defects in the cup – they can sometimes have an intense earthy flavour due to the soil they have been dried on! Traditionally, it has been washed coffees that have attracted higher prices due to their cleanliness and uniformity, though more and more specialty buyers have invested in the natural process due to the potential for flavour profile experimentation.
If done properly whereby ripe cherries are laid on raised beds in thin layers and regularly turned to reduce the risk of mould growth, natural processed coffees can have the most incredible cup profile with flavours such as ripe strawberry, mango and blueberry being commonplace. The cherry is dried with all of the layers intact which means there is a certain amount of natural fermentation occurring in the bean in its own environment – many enzymatic bi-products are absorbed from the mucilage into the heart of the coffee bean which can result in an incredibly distinct flavour profile. Once dry, the cherries will resemble raisins and when they have reached this state, the coffee is hulled to remove the outer layers before being sorted in a ‘dry mill’ for shipment.