So many factors work together to give your coffee the distinct characteristics it has. Plant variety (or cultivar), type of soil, altitude, sun exposure, annual rainfall… these are but some of the parts that form the rich tapestry of flavours and aromas you’ll find in your cup.
Looking at the label on a bag of coffee, you might notice that it notes how the beans were processed. You might see words like “honey”, “washed”, “sun-dried”, “natural”, “pulped-natural”. What does this all mean, and is it important? Well, processing methods do indeed have a significant effect on what you taste in your coffee. Recognizing the differences in what you’re tasting, and knowing why those differences exist, is a real game-changer.
Coffee processing differs throughout the world. Some producers have been using the same process for generations, and their chosen method is based on tradition, or other factors such as access to water or equipment, rather than the potential influence on the cup. Other producers are opening up to different processes and experimenting with them in an attempt to uncover new and exciting flavours in the coffee.
To better understand the different processes, it helps to know what we are working with. Each coffee bean is essentially one half of the seed found at the centre of a coffee cherry (except for anomalous peaberry beans, which are whole, lone seeds). Covering the bean is a thin, papery layer called the endocarp, or, more commonly, the parchment (this is most often removed by a machine called a huller before export. Hullers are not easy to come by outside of coffee producing areas, and removing parchment by hand is not a journey you want to embark upon. Trust us, we’ve tried). Surrounding the parchment is a slimy layer most commonly known as mucilage. Then you’ve got the layer of pulp, or mesocarp, and finally, the outer layer, or skin, of the cherry, called the exocarp. Various parts of the coffee cherry are removed at varying stages of each process.
Now that we’ve got the terminology down, here is a rundown of the different processes and how they affect what’s in your cup. Many of these have different names depending on the country, but they’re essentially the same.
The natural process is the most passive of the processes, but the result is anything but. What makes a sun-dried coffee interesting is that the taste of the cherry comes through in the cup. This is due to the fact that the coffee is dried with the cherry intact. The cherry is often not removed until right before export, at which point the dried pulp and parchment is mechanically removed from the bean. These coffees are generally smooth, fruity, and sweet, with a heavy body and lower acidity.
80% of Arabica coffees from Brazil, Yemen, and Ethiopia are natural processed, and have been for centuries. While it was considered a lesser method in the past (the argument being that washed coffees produce a cleaner, more balanced cup), it is beginning to see growth in regions outside the above-mentioned, with more producers wanting to experiment with different profiles, themselves encouraged by forward-thinking green coffee buyers.
Honey processing originated in Costa Rica and is lately gaining traction throughout Latin America. The mucilage, if you’ll remember, is the slimy layer coating the coffee beans. This substance is quite sweet and is often called honey (although it is more slimy than sticky), hence the term honey process. There is not yet proper standardization within the honey process, so it gets a little complicated, but the most important thing to retain is that, basically, the bean is dried with some or all of the mucilage still adhering to the parchment. One variable is the amount of mucilage left on during drying. Producers claim anywhere from 40 to 100%, but it is generally a fairly arbitrary estimate and should be taken with a grain of salt. Another discrepancy is what is meant by yellow, red, and black honey. In some regions, this can refer to the amount of mucilage that is left on the parchment. Yellow honey would have little of the mucilage left on, and black honey would have the most, with red in between. Drying times are proportional to the amount of mucilage left on, with black honey boasting the longest. Other regions use the terms yellow, red, and black honey to denote how much sun exposure the drying coffee has received, and consequently, how long the beans are left to dry. Black honey beans receive the least amount of sun, and are often dried under tarps on raised beds for a duration of roughly two weeks, while yellow gets ample sun and takes about 8 days to dry. Again, red is somewhere in the middle. The resulting coffees – named for their golden, reddish, or deep maroon hues caused by caramelization of the sugars in the mucilage – often feature slightly more acidity than their natural counterparts, but much less than their fully washed brethren.
You could say that the wet process is the most transparent of the processes, in the sense that it allows you to see right through to the essence of the bean itself. When coffee is washed, the pulp is mechanically separated from the beans (by a pulper, who knew?), and the sugars found in the mucilage are then removed through natural fermentation. This is achieved by letting the coffee sit in tanks for a few days, either underwater (wet fermentation), or in its own juices (dry fermentation). It can also be removed mechanically, through scrubbing or pressure washing. This method is lauded by some for its reduced water usage and consistency in cup (as it eliminates the risk of over-fermentation). However, its advantages are often mitigated by a marked lack of flavour.
During fermentation, enzymes work to loosen the mucilage from the parchment. The coffee is then washed to remove the loosened mucilage, and dried, in the sun on large patios, on raised beds, or in mechanical dryers.
Dry fermentation tends to produce a sweeter and more complex cup, while wet-fermented coffee is brighter and sharper. On the whole, though, because it is not muddled by the flavours of the cherry, wet processing is known for producing a clearer cup, with higher acidity. It also tends to be more consistent in flavour.
There you have it. We hope this has provided you with a clearer understanding not only of what’s on your coffee label, but also what’s in your cup.