Processing of coffee is the method converting the raw fruit of the coffee plant into the coffee. The cherry has the fruit or pulp removed leaving the seed or bean which is then dried. While all green coffee is processed, the method that is used varies and can have a significant effect on the flavour of roasted and brewed coffee.  In General, coffees processed by the wet method will be brightest, driest, and cleanest tasting. Those processed by the ferment-and-wash wet method will be next brightest and driest, though often a bit fruitier and more complex. Coffees processed by the semi-dry and the dry methods tend to be fruitiest, most complex, and heaviest in body owing to longer contact with fruit residue during drying.

Dry-Process: The dry-process (also known as the natural method) produces coffee that is heavy in body, sweet, smooth, and complex. The dry-process is often used in countries where rainfall is scarce and long periods of sunshine are available to dry the coffee properly. Most coffees from Indonesia, Ethiopia, Brazil, and Yemen are dry-processed.

Wet-Process: Wet-processing coffees is a relatively new method of removing the four layers surrounding the coffee bean. This process results in a coffee that is cleaner, brighter, and fruitier. Most countries with coffee valued for its perceived acidity, will process their coffee using the wet-process.

Pulped Natural: The pulped natural method consists of pulping a coffee, but emitting the fermentation stage to remove the silverskin. This results in a beverage that has characteristics of both a dry- and wet-processed coffee. It is often sweeter than wet-processed coffees, has some of the body of a dry-processed coffee, but also retains some of the acidity of a wet-processed coffee. This type of processing can only occur in countries where the humidity is low and the the coffee covered in the sweet mucilage can be dried rapidly without fermenting. Brazil has made this method famous and produces some of the best pulped natural coffees in the world. All twenty winners of the Gourmet Cup competition in Brazil in 2000 used pulped natural coffee processing method.

Re-Passed: There is another type of coffee that has emerged on the market called re-passed or raisins. These coffees are floaters and are usually discarded with the rest of the floaters. However, they have a flavour profile that some of the world’s best experts find to be much sweeter than traditional pulped coffees. The cherries float because they have dried too long on the tree before being collected. This, however, allows the bean to interact with the mucilage for a longer amount of time before the start of fermentation. The beans are removed from the rest of the floaters using a barrel system developed by Eduardo Sampio in Brazil. The coffees are then re-passed and pulped. They can then be washed or used as pulped naturals. The availability of the curiously sweet re-passed coffees is very limited since it is mainly experimental at this time.

Comparison: The vast majority of coffee producers will claim the virtue of their coffee processing method. In Guatemala, for example, dry processing is a bad word and rightly so. Due to their high humidity a dry processed coffee will almost definitely be fermented, which is why only their lowest grade coffees are dried without pulping. However, in Brazil, dry processing results in a sweet, complex, and heavy-bodied coffee that is almost essential in any good espresso blend. The only conclusion that one can make is that every region has its own proper coffee processing technique and that the processing technique should help attain the flavour profile that is desired by the producer and consumer.

Other Coffee Flavour Contributors: The coffee processing method is usually the single largest contributor to the coffee flavour. The differences between a washed and dry-processed Brazilian coffee from Sul de Minas will generally be more distinct than the differences between two wet-processed coffees from two different regions. However, the microclimate and soil are the next major contributors to the flavour profile of a coffee, and assuming processing is done correctly, they become the most important contributors to the flavour profile.