Raw Materials: The Ins and Outs of Drying Coffee
In our Raw Materials series, Merit's Director of Green Coffee Jamie Isetts writes on green coffee, origin, and the finer details that make our coffees and partners so unique. Have a question? Email email@example.com.
Our Gold Lantern release of El Encanto Natural is made possible with an unusual approach to drying. Producer Juan Saldarriaga’s farms are in a wet, overcast climate that would normally rule out this berry-forward process. But how does coffee go from wet to dry? For some context, let’s delve into the drying process and how it’s used across the world.
As soon as ripe coffee cherries are picked off of the tree, they begin their long journey to become the material we roast at the warehouse. Broadly, the steps that transform a cherry to a dried green bean are called “processing.” The style and quality of a coffee’s processing has the most noticeable effect on flavor and longevity.
The drying step is a crucial element of processing. Producers dry coffee to a fraction of its original weight so it can be stable for transport without the risk of fungus and mold. But just like roasting, how coffee is dried matters. Each drying approach has a huge effect on the taste profile of the coffee, its consistency, and how long it will retain its flavors. At this stage, the coffee is often referred to as “parchment,” since this intermediary casing layer is still intact over the green bean.
Basic approaches for drying coffee
Drying patio at Finca Chelin, Oaxaca, Mexico.
Mostly seen in Latin America, these traditional patios are made of flat concrete. The parchment is spread out in a thin layer and mostly dried by the heat and light of the sun. Since the coffee is only exposed on one side, workers must turn it with a rake or a paddle throughout the day. Being on the ground also leaves more opportunity for the coffee to be exposed to dirt and stepped on by people and animals.
A full-sun raised bed at Kinyovu washing station, Kayanza, Burundi.
Raised drying beds (sometimes called “African beds,” since they originated there) lift the entire drying operation up off the ground. Importantly, the flat part of the bed has a layer of mesh or loose-weave cloth rather than a completely closed surface. This allows for airflow on more of the coffee’s surface areas, drying it more evenly. Since most raised beds are about waist-height, workers can more turn the coffee more easily and inspect for defects faster.
Advanced Tactics: Using Shade, Thickness, and Multiple Levels
Just like in roasting, good drying is about the rate at which things happen. Think of the difference between cooking a steak on one level of heat versus moving from high to low. In both scenarios, you cooked the steak, but how you do it affects the flavor. Sophisticated producers will employ different tactics to expose the coffee to a specific pattern of light, heat, and humidity throughout its drying cycle.
Coffee parchment being dried and sorted under a roof for shade at Mpanga Washing Station, Kayanza, Burundi.
Some producers will dry coffee on beds or patios that are open on the sides, but partially or fully protected from sunlight overhead. This allows producers to control the amount of sunlight (and heat) that hits the parchment at any time. “Shade drying,” as it’s known, can also reduce the UV exposure during drying, which some producers think can be more detrimental than drying by airflow.
A parabolic dryer at the farm of the Fernandez family in Santa Barbara, Honduras.
A structure like this can also help with the opposite situation. In wet areas, parabolic or house dryers are covered in translucent plastic that lets light in, keeps intermittent rainfall out, and allows wind to blow through open sides as the coffee dries.
Also at Mpanga Washing Station, a honey-process coffee is dried in "pyramids" to slow down drying from the scorching sun.
Producers also manipulate the thickness of the parchment layer to get different affects or protect from too much sunlight tor moisture. Choosing the right level of thickness depends on the local climate and may be changed several times throughout the day.
Since drying is all about surface area, having enough space to dry everything is a common bottleneck for producers. One interesting way to solve this problem? Go vertical! Multi-level drying beds create more space for drying coffee. Yet, the really interesting application of multi-level beds is about manipulating heat, sun exposure, and humidity. Coffee can be moved to another level at various stages in the drying process to expose it to different conditions, changing the rate of drying.
Multi-level raised beds at Finca La Senda, Acatenango, Guatemala.
All of these methods are still somewhat exposed to the climate outside. The level of sunlight or changes in humidity are not completely within the producer’s control.
Closed Systems: Machine Drying 2.0
Machine dryers coffee have existed for over a century. The most traditional style, called “guardiolas,” work very similarly to a coffee roaster. Wet parchment rotates in a turning drum over a heat source as air flows through. Since these systems are more focused on drying the coffee quickly, they usually deteriorate the quality. But the idea of a drying system that is independent of the climate provides a new frontier for intrepid producers with resources for experimentation.
El Encanto Natural is a successful example. Saldarriaga bought a mechanical dryer designed for fruit that dries with cold air and allows him to control both temperature and air flow. The lot we purchased was dried on this system, and the results are phenomenal. Careful drying allows for clean, crisp flavors along with the rich berry notes that make naturals so memorable. Saldarriaga’s wet climate is not ideal for traditional natural production, so this system opens up a whole new flavor profile for him.
We at Merit are stoked to share the El Encanto Natural with you this season! If you’re in the mood for something fruity, we’ve got you covered.