Coffee processing plays a crucial role in determining the flavour profile and characteristics of the coffee we enjoy in our cups. From the moment coffee cherries are harvested, farmers employ various processing methods to transform the raw fruit into the beans we grind and brew. With constant innovation and experimentation, coffee producers strive to enhance the quality and uniqueness of their coffees. In this article, we will explore the three main coffee processing methods and delve into how they influence the final cup of coffee.
Natural or Unwashed Coffees
Also known as the dry process, natural coffee processing is characterised by its simplicity and minimal intervention. During this method, the coffee cherries are left intact, and the beans undergo a drying and fermentation process within their skin and mucilage (fruit pulp). This natural fermentation takes place under controlled conditions for a period of 25 to 35 days, depending on the climate. Once the beans have dried, the pulp and skin are removed through a process called dry milling.
Natural coffees often exhibit inconsistencies due to the higher risk of mold development during the extended drying period. Each bean possesses its own unique levels of sugars and alcohols, which can affect the overall uniformity of the cup. However, when properly handled, natural processing imparts a distinct and complex flavor profile to the coffee, often characterised by fruity and vibrant notes.
Wet Process or Washed Coffees
The traditional wet process begins when fully ripe coffee cherries arrive at the mill. The cherries’ skin is mechanically removed using a depulper, separating the beans from the fruit. Following depulping, the beans undergo fermentation in clean tanks to remove the remaining mucilage (sugars). This fermentation period typically lasts between 12 to 48 hours. Once fermentation is complete, the beans are thoroughly washed to eliminate any remaining traces of mucilage.
Various methods can be employed to dry the washed coffee beans, such as patio drying, raised bed drying (African method), or mechanical drying. A dry climate is essential for producing high-quality washed coffees. The washed process yields a clean and transparent cup, characterised by a bright acidity and liveliness. These coffees are often cherished by coffee enthusiasts for their pronounced flavour clarity.
Honey Processed or Honey Coffees
The honey process is a unique and relatively newer method that involves the removal of the skin and pulp from the coffee cherries, while retaining some or all of the mucilage (sugars). After depulping, the beans are dried rapidly for a shorter period, typically around 10 to 15 days. During this drying phase, the beans must be regularly agitated to prevent the growth of mold.
Honey coffees can exhibit different levels of coloured parchment during the drying process, often categorised as yellow, red, and black. The darkness of the parchment corresponds to the remaining mucilage content and imparts complexity to the resulting cup of coffee. Honey coffees strike a balance between the body and sweetness of natural coffees and the acidity found in washed coffees, offering a unique sensory experience for coffee enthusiasts.