Once coffee is removed from the tree there are three main ways to process the cherry before the bean is ready to be roasted. There is considerable variance within each of these three branches of processing but on a macro-level the methods are grouped into the following categories:
This is the process by which the pulp is removed from the bean. Essentially, the coffee cherries are immersed in water where the bad or unripe fruit will float and the ripe ones sink. The bad are removed and the good are channeled to an area where they flow through a screen that removes the pulp. Due to the large volume of cherries being processed at one time many beans will still have a significant amount of the pulp remaining. That layer is either removed by another round of washing or through ‘dry fermentation’ in which the beans are dried to the point where the mucilage is naturally broken down.
While this form of processing uses a lot of water it generally guarantees a clean and consistent cup. It is easy to monitor the variables in this process which makes it desirable for the processor and a considerably consistent product from one harvest to the next.
This process leads to remarkably sweet, fruity, or exotic flavors and tends to lead to the highest cupping scores. It is a very delicate process to monitor though and can have a great variance in flavor profile from harvest to harvest.
Simply stated, naturally processed coffee is coffee that is removed from the tree and dried without the bean being separated from the cherry. If the cherry is not dried right it can lead to a pungent and harsh taste or a brittle bean that loses its flavor and easily burns in the roasting phase. If successfully processed, naturally dried cherries typically lead to a less acidic and heavy body in the cup.
Describing this method can be confusing because there is a lack of consensus about its meaning. Some call it ‘honey-ed’ because of the fermentation it goes through in the mucilage and some call it ‘honey-ed’ because of the slimy texture of the mucilage. Either way, this process refers to the method in which the bean and cherry are separated but the mucilage is left on the bean. Typically, if the pulp is removed by water and then dried it is called a semi-wet process…and if the pulp is removed by means other than water it is called honey processed. Again, this is overly simplistic but is how the terms are most commonly used. This method can lead to some wildly unique flavors if processed correctly. If the process is not managed well, the spectrum of tastes can range from highly acidic sours (if fermented too long or with pulp not properly removed) to very bland and un-complex flavor notes.
Amongst our experience with the various processing methods we have found the honey process to be the most difficult to reproduce the same cup quality and flavor profile from lot-to-lot and harvest-to-harvest.
photo cred: Bryon Lippincott