As I listened in on a tour yesterday the conversation about natural or washed coffees came about. It dawned on me that not everyone may know or understand the differences as to how coffee is processed (after the cherries are picked). We talk a lot about sourcing the best coffee, roasting, and brewing with fancy high tech gadgets but leave out an important element that effects what’s in that cup of Joe your drinking.
There are three major types of processing, washed (or wet-processed), natural (or dry-processed), and semi-washed (or pulp-natural).
These terms may mean different things to different people and even from country to country their definitions may change a bit. So the goal here is to give you an introduction into the process after the cherries are harvested and not bore you with each country’s specifics.
First the beans must be picked or harvested from the trees on which they grow. Usually the farmer is only hand picking the ripe (red) cherries and leaving the unripe (green) cherries to ripen a bit longer. Under ripe cherries can give a grassy like taste in your cup while over ripe ones can taste a bit moldy in your cup. Timing is everything here. Some countries will even use a machine to just strip the branches of all the cherries and then have workers sort them according to ripeness.
Washed (wet-processed) coffee goes from harvest to the mill, where the cherries are sorted and processed through a series of steps. The first step submerges the cherries in water and the unripe cherries float to the top and are removed. The cherries are then sent to the depulping stage which removes the skin and the pulpy layer beneath it. What remains from the depulping stage are beans that are covered in a sticky layer called mucilage. The beans then go to the fermentation process where they are placed in fermentation tanks and soaked for a period of time ranging from 12-48 hours. The natural enzymes will work to soften and loosen the mucilage so it can be removed. In the final step the beans are dried either by mechanical driers (a much bigger version then the one you have at home) or spread out on a patio and dried by the sun. When dried, the beans are ready for sorting, grading and bagging.
* The Washed process is known for producing cleaner and brighter coffees.
Natural (dry-processed) coffee is predominant in countries that don’t get a lot of rain or where water may be scarce. Obviously it’s the opposite of the wet or washed process. The cherries are picked, cleaned and laid out on patios to dry for up to four weeks and raked continuously to promote even drying. As the berries dry the farmer will keep an eye on moisture content (usually 11% is ideal). Once the desired level of moisture is reached the hulling process begins. Hulling is the fancy term used to describe the removal of the parchment layer (or endocarp) of the dried cherries. After this, some farmers will even further polish up the beans by removing the silver skin left after hulling. If left on it will be removed during the roasting process and is called chaff (great for gardens by the way). Either way, when finished the beans are ready to be graded, sorted, and bagged (more on that later).
* The Natural process is known for producing bolder, sweeter coffees.
Semi-washed (pulp-natural) coffees are where the outer skin is removed, similar to the wet process but omitting the fermentation. Once the skin is removed, the pulpy mucilage is left to dry on the bean. This process contributes to a fruitier, yet heavier bodied, earthy type of coffee. Kind of like getting the best of both worlds if you will. This is one of the processes used in Brazil, and parts of Indonesia.
What’s amazing is that regardless of what origin, process, roast profile, and brew method that is used, there is so much that can go wrong. Each step along the beans journey to your cup is so vital to the outcome that it should only extract appreciation from our busy little souls.