The SL variety was brought to Kenya for cultivation by Scottish and French missions between 1934 and 1963, where it was developed by the Scott Laboratories research organisation - hence the name SL. There are several varieties, mostly based on Moka and Bourbon types.
After harvesting the ripe cherries, this naturally processed coffee was dried on patios, complete with the fruit and its skin. This imbues the flavour of the fruit into the beans themselves, which, after being de-pulped, carry a tropical, juicy flavour profile. It's a more environmentally friendly processing method as it uses substantially less water than washed processing.
After harvesting, they are slowly dried in the sun so that all the sweetness of the ripe cherry can be absorbed. After about 10-12 days of drying, the cherries are plumped - the dry skin separated from the beans - and stored for a few more days. The resting period must be done at a certain temperature so that the beans reach a certain level of moisture.