Common Coffee Processing Methods
One could write an entire book about coffee processing, in fact many have. But, for the sake of brevity this will be a simple look at arguably the most important step in coffee production.
Coffee processing is often overlooked by casual coffee drinkers and even unknown to many folks. Coffee processing is the method in which you de-pulp coffee beans. The coffee beans we grind up and brew every morning are the seeds from a tree called Coffea, a plant that belongs to the Rubiaceae family of flowering plants. The Coffea plant has anywhere between 25 and 100 different species. The most popular two are Arabica and Robusta, but experts are unsure about exactly how many there are or how to differentiate between many of them. This plant, as avid coffee drinkers are already familiar with, is grown predominantly in Central and South America, as well as in Africa, Asia, Caribbean nations, and even in some parts of Australia. The Coffea plant produces cherry like fruits, which contain large seeds, or what we know as coffee beans. The fruit produced by the plant is edible, but these cherries have very high levels of caffeine, are rather sour, and there isn't actually much fruit. Most of the density of the cherry comes from two beans encased in the pulp/parchment.
Now that you know a little bit about the plant itself and the fruit that it produces, you may be wondering: how do people get these beans out of the fruit and prepare them for the next stage in coffee production? This is where coffee processing comes into play. As mentioned earlier, we could spend ages talking about processing, especially with the dawn of experimental coffee processing. But to keep it simple, I will discuss the four most common ways to process coffee and get the beans that we desire out of the cherry.
Natural (also known as Dry) Process
The most common method of coffee processing is the Natural Process. Naturals dominate the Brazilian coffee industry, the world’s largest coffee producer, so casual coffee drinkers may be most familiar with this process. This method takes the longest amount of time, anywhere from 3 weeks to two months. A coffee that has been “Naturally Processed” is one that has essentially been allowed to sit out in the sun fermenting as the the pulp around it decomposes and falls away. While this process may seem very hands off, it actually requires a great deal of attention in order to prevent the coffee from molding. A coffee producer can't just leave the cherries out and come back 6 weeks later expecting a good result. It requires the producer to be frequently moving the cherries around, not just turning them over but also switching out the drying beds they reside in. During the process of fermentation, the cherries will discharge various sugars onto the beans, giving the coffee sweeter and fruitier flavor profiles. Once the fermentation period is done, machines remove any remaining pulp and skin from the cherries. Natural Processed coffees can contain more complex flavors than the other methods. This is why some really great coffee producers tend to go with Natural Processing for their coffees. This process requires extra work and dedication, but the flavor profiles that can be produced at the end make it well worth the commitment.
Washed Process
Also referred to as a wet process, Washed Process coffees get processed much faster than the Natural/Dry Process, taking about 10-20 days to complete. Once the coffee producer has finished sorting the fruits, picking out the best and most ripe ones, the cherries immediately get completely de-pulped. This doesn't take much more than a few hours, and the freshly de-pulped beans are placed into large tubs of water. They sit in the water until all of the remaining mucilage gets washed away. After that's completed, the beans are laid out on drying beds in the sun to dry for a number of days before they are ready to move on to the next phase of coffee production. Washed coffees tend to have less complex flavors going on. However the flavor profiles tend to be very balanced and crisp, often creating a cleaner cup of coffee. The coffee is more balanced in acidity and body than other methods, and you won't have flavor profiles that pull too much in any direction. That's not to say that you can't find really good and flavorful Washed Process coffees. Some of the best coffee I've had have been Washed, and many top industry professionals love a good washed coffee. Because of the machinery required to de-pulp and then wash the beans, the costs for this method can get considerably expensive. This is why many producers opt for the Natural Process.
Wet-Hulled Process
This method of coffee processing is almost exclusively used in Indonesia, more specifically for coffee from the Sumatra region. The reason for implementing the Wet-Hulled process is it's better suited for countries that have humid climates which make the Natural Process harder to do. It's similar to the Washed Process in that the goal is to de-pulp the beans as soon as they are finished being sorted. A de-pulping machine removes the skin and fruit, but leaves behind a thin layer of mucilage. The beans are allowed to sit briefly in large bins, often made of plastic or a similar material, where it gets a chance to ferment with the mucilage still intact, keeping a lot of moisture around the beans. Once it's been allowed to ferment for a bit (the amount of time is up to the producer, usually 12-24 hours) it is then put into a hulling machine which removes the remaining mucilage, and the coffee is subsequently put on drying beds where it sits until the coffee has reached a moisture level of 12-13%. This added time the coffee beans get with the mucilage creates a coffee that has more body to it, and this also brings out a hazelnut flavor profile. This is why coffee from Sumatra is often associated with having a profound hazelnut taste.
Honey Process
This is an emerging process that's become more and more popular in recent years and has seen various modifications (we’ve seen things like “Yellow Honey” or “Black Honey” processes, each with their own nuances and complexities). It's essentially a hybrid between the Natural and Washed Processes. Once picked and sorted, the beans again get immediately de-pulped, like in a Washed. However, rather than being put in water tubs, the coffee is laid out to dry in the sun. The mucilage remains intact as the beans dry for about a week, being raked and moved around frequently during this time. This allows the beans to ferment with the mucilage still covering them. After the week has passed, the beans are put into a hulling machine, allowing for the remaining mucilage to be removed. During the week-long drying period, the beans are interacting with the mucilage taking on many sugars from it, creating a very sweet coffee. This is where the name "Honey" comes from. Honey Processed coffees have very complex and wide-ranging flavor profiles. Coffee drinkers will experience a much more acidic coffee when drinking Honey Processed beans. Notes of syrup and fruitiness are very pronounced, the coffee is clean, and the coffee drinking experience is noticeably different from other methods of processing. As it gains popularity, it'll be interesting to see how different producers will approach Honey Processing as there are so many different components that can be altered throughout the duration of the process.
So that was coffee processing in a nutshell. This won’t be the last time I discuss processing methods. Recent years have seen a boom of experimental processing and various anaerobic processes, which I hope to cover in due course. But, as an overview of the main four processing methods you’ll encounter, I hope you learned something new, and stay tuned for the next Coffee Talk. As always, if there's a topic you want me to cover in this blog, feel free to DM me on Instagram or send me an email. You can also get in touch via the "Contact Us" tab on this website.