Many factors affect coffee quality, such as growing conditions, harvesting and processing. The three major processing methods are:
NATURALS A natural processing means that after the coffee cherries are picked, they are dried as they are, without removing skin or mucilage. Drying happens in patios or on raised beds where coffee is left to dry in the sun. It usually suits countries like Brazil, with scarce rainfall and long periods of sunshine during harvesting season. Also known as dry process, it’s the oldest and simplest way to process coffee, but it’s also very hard to get it right as in order to achieve high quality, beans must be carefully selected at the precise stage of ripeness. The cherries are laid out to dry and frequently turned to ensure even drying and prevent mould. It may take up to four weeks before the cherries are dried to the optimum moisture content, depending on the weather conditions.
CUP PROFILE: During the drying process sugars and flavours in the fruit are concentrated and absorbed into the bean, imparting heavier body and powerful yet refined fruit flavours with substantial body, sweetness, smoothness and complexity.
SEMI-WASHED The method was pioneered in Brazil around twenty years ago, where it was originally called Cereja Descascada or “peeled cherry”. This is because the process involves removing the skin of the fruit before letting the coffee dry with almost all the pulp still on the beans. The process can also be called pulped natural or honey. The honey process has several sub categories depending on the amount to mucilage left on the beans (from back honey, with more mucilage, to red and finally yellow honey). It’s essentially a middle ground between the natural and washed processing methods. During the natural (or dry) method, the beans are dried entirely in their natural form, while the washed (or wet) process sees all the soft fruit residue, both skin and pulp, removed before the coffee is dried. This processing method is suitable for countries with low humidity, as coffee covered in mucilage needs to dry quickly to avoid fermentation. One of the biggest advantages of this process is that, by removing dried and green beans, you increase the cup quality and decrease the possibility of defects. However, when compared to the natural process, it’s more expensive and requires expensive machinery and and energy.
CUP PROFILE: Fine elegant attributes of a top washed coffee, coupled with the more substantial body and fruit sweetness of a natural. When done correctly, the process results in a very pleasant cup profile with accentuated sweetness, body and citrusy overtones. These coffees normally have the body of a natural coffee and the sweetness and acidity of washed coffees.
WASHED Washed coffee, also referred to as the wet process, is when the coffee cherry is pulped by a machine referred to as a pulper. This means that the outer layer of skin is removed and the bean with its mucilage is then fermented in water for around 48 hours. After the fermentation process, the bean is then washed from its mucilage and what is left is the bean surrounded by two additional layers, the silver skin and the parchment. When dried in the sun coffee is most often spread out in rows on large patios or raised beds where it needs to be scraped every six hours to promote even drying and prevent the growth of mould. Drying coffee this way has the advantage of allowing air to circulate better around the beans promoting more even drying but increases cost and labour significantly. After the drying process, the parchment skin is easily removed by hulling machines and the beans are bagged and shipped.
CUP PROFILE: The process softens the sticky cherry pulp surrounding the beans and enhances acidity and any of the finer floral aromatics a coffee may have. In general, the difference between each of the techniques is the amount of mucilage (or mesocarp) that is removed from the coffee cherries. These are the major techniques but nowadays innovations are many and coffee can be processed with many variations inside this main processing techniques.