Coffee Processing Methods
There are several ways coffee can be processed, with each method highlighting different characteristics such as acidity, body, sweetness and fruity/floral notes. Processing methods are chosen by producers based on their available resources, and the method that best showcases the unique flavour profiles of their coffee.
The Natural (or Dry) method involves drying and fermenting the coffee beans in their full cherry form, before removing all layers in a process called hulling. This results in fruity and “boozy” flavours, a heavier body and enhanced sweetness as the coffee benefits from the fermentation of the sugars available in the entire coffee cherry.
The Washed (Pulped) method uses wet fermentation and multiple pieces of machinery to enhance the acidity, clarity of cup and fruity/floral characteristics within coffee. During this process the skin and fruit of the coffee cherry are removed by a pulping machine, and the seeds covered in a sticky layer of mucilage are then allowed to ferment in tanks filled with water. Once the fermentation period has ended, the seeds are washed to remove any remaining mucilage and left to dry on terraces within their parchment (a layer similar to the red skin of a peanut). This parchment is what helps to keep the clarity of the coffee, and is then removed at a later time just before exportation in a processed called milling.
The semi-washed (honey/ pulped natural) method of coffee processing is considered a newer, hybrid version of both of the above processing methods. During this process the skin and fruit from the cherry are removed before allowing the coffee beans, still in their parchment and mucilage layers, to dry (either in the sun or within a storage area). Often the producers will remove part of the mucilage to manipulate the finished flavour profile of the coffee. The terms yellow, red or black honey are often used to describe the amount of mucilage that is left on the coffee beans – with yellow being the least and black being the most. Once ready, the mucilage is washed off and the coffee beans are then given a final dry. This process is said to help retain the sweetness and fruitiness attributed to naturally processed coffees, while still retaining the brightness of acidity and clarity of cup experienced with washed coffees.