Coffee Processing Methods: Natural, Washed, Honey, and More

Many of us have become invested in our favorite caffeinated morning beverage. But how many of us have looked further into this delicious cup? Where do these unique coffee beans come from and what coffee processing methods are used before they become a part of our morning routine? There is probably a lot more going into it than you think! 

Coffee Production 

To start, coffee beans are not brown before they are roasted—they start as pale green and take on the brown color they are known for as they reach temperatures close to 400 degrees. Unroasted green coffee starts as dense, hard, and inedible, and it is actually not much of a bean at all. It is the seed of a fruit that grows on coffee plants in many parts of the world.  

The coffee plant, of the Coffea genus, is a flowering tree that produces red “cherries,” much different than the cherries you find at your local grocer. The small, oval, caffeinated fruit contains two seeds that we harvest it for. Steps are taken after this harvest to transform the fresh red cherries into dried, pale green coffee beans that are the commodified product for roasters everywhere. This step is simply named: processing.   

What is Coffee Processing? 

Unique coffee processing methods exist in different regions of coffee production, taking fresh, red cherries, and lending dry, green coffee beans—ready to be milled and distributed. Several layers get removed, including the cherry skin, the flesh (pulp), the remaining mucilage, and the parchment—a casing that wraps the beans in a protective barrier until they have been dried out. Depending on the region, farmer, and resources available, one of many processing methods may be used. 

Natural Process  

Natural coffee processing is the oldest, and most traditional way of processing coffee. Often called a “dry” process, it involves leaving the fruit of the cherry completely intact until the whole cherry is completely dry. Farms and processing facilities may have nuanced methods of carrying out this process, but in general, full cherries are laid out in the sun to dry while being turned regularly to regulate airflow and prevent molding. Once the coffee is dry, the shriveled fruit, dried-up mucilage, and parchment will be removed in a stage called milling, and the green coffee is stored for export. This is a common process in arid climates where there is little access to water and is known for producing coffees with much more fruity flavors, along with earthy and wild-tasting notes. This processing method has a reputation of being unpredictable with much higher levels of fermentation taking place. The flavor profile may be funkier than a producer bargained for, and lots have more risk of rotting and molding under this method.   

Washed Process 

The washed coffee process is a more resource-intensive process. Sometimes called a “wet” process, it involves removing the fruit flesh in a step called “depulping,” and then washing the sticky mucilage layer from the parchment-covered seed before the coffee is dried. A machine removes most of the flesh, and the coffee is moved to a water trough, where the remaining mucilage is washed away. The coffee beans are then laid out to dry before being stored for export. This is a much more controlled process than the natural processing method and is known for producing clean coffees with more mellow-tasting notes, like chocolate, caramel, and nuts. 

Pulped Natural Process 

Common to Brazil, this processing method was first introduced to minimize the unpredictability and risk of unpleasant flavors often associated with natural process coffees, while using less water than a fully washed process. It involves mechanically depulping the cherries but leaving a layer of pectin and small amounts of flesh intact on the bean for the drying process. After depulping, coffee goes to dry on patios or raised beds. This is a cost-effective and lower-risk way of producing coffee. 

Wet-Hulled Process 

Also called the Sumatra Process, the Wet-Hulled coffee processing method is traditional in Indonesia. This method imparts unique qualities to the green coffee. For this method, coffee is depulped a day or two after harvest. With its mucilage remaining intact, the wet coffee beans are then stored in plastic tanks, rolled tarps, or jute bags until they are sold to a mill. The unique storage method and the humid environment of Indonesia increase the coffee's moisture content to 35-50%, much higher than the normal 10-12% moisture content of coffee processed elsewhere. It also elicits more fermentation than other processing methods, creating earthy and distinct flavor profiles. 

Honey Process 

Very similar to the pulped natural coffee method, this process starts by roughly depulping the cherry and leaving parts of the fruit intact. This process is named for the sticky, golden-colored residue surrounding the beans as they dry, and not for any involvement from pollen-collecting bees.  

Within honey processing, however, there exist various levels of cherry removal. These differences are distinguished by colored categories, with more fruit flesh being removed as the color gets lighter. 

Anaerobic Process

The anaerobic method is a new and experimental way of processing coffee where farmers can really express their creativity. Coffee cherries or depulped beans are sealed in airtight containers to eliminate oxygen during fermentation. The mucilage or pulp will be fermented and eaten by bacteria, creating lots of carbon dioxide. This further decreases oxygen levels in the tank, allowing anaerobic bacteria to thrive, and increased fermentation to occur. The coffee can be sealed in the tanks for just a few hours, up to several days; after which, they will be removed from the tanks and dried in raised beds for 2-6 weeks. Anaerobic coffee fermentation processes are generally risky and produce small microlots of coffee that may be more expensive than more traditional processing methods. These coffee lots are usually very sweet, and bright, and have a funky/fermented complexity to them.

Where Do I Go From Here? 

You are probably already inclined toward a particular coffee processing method, even if you don’t quite know it yet. Start with the coffee flavor profiles you know you love and reach toward a new coffee that utilizes its corresponding processing method.  

If you enjoy fruity and bright coffees, reach for a new natural or anaerobic process coffee. Are you a fan of coffees that are sweet and clean? Try a new washed process coffee. For something in the middle, with balance and complexity, find a honey processed coffee. 

Single Origin Coffees are one of the best coffees to buy when trying a new coffee processing method. While single origin harvests are each unique, it’s easy to branch out to new regions when you know the details that make them take on specific profiles.