Types of Coffee Processing
What do the terms “washed”, “natural”, “honey”, etc. mean when people use them to describe coffee beans? And why should you care?
The way ripe coffee beans are processed before sending them across the ocean can have a significant impact on the ultimate aroma, flavor and body you taste in your cup. Let’s take a look at the 6 major coffee processing methods and find out why they can help you select your next coffee variety. For more information, check out the videos at the end of each section.
Natural Process
This is the oldest and most sustainable processing method. Ripe cherries are picked and laid out on raised platforms in the sun for 3-6 weeks to dry, with daily regular turning and raking. The cherries first swell then shrink as the moisture is reduced, similar to what happens when drying grapes to raisins. When they reach the leathery stage, they’re shipped to the mill, where the cherries are de-hulled, removing all of the fruit and parchment layer from the seed. Then, it’s bagged and shipped to the warehouse to await shipment.
This process is often used in countries where the dry weather is conducive to long drying periods, and where farmers have limited access to clean water. The washed processes (see below) require water, as well as electric machinery to complete, which might be unavailable. This process is commonly used in areas like Yemen and Ethiopia.
Natural-processed coffees are generally fruity and full-bodied, with low acidity and exotic flavors. They’re quite sweet, thanks to the infusion of the natural sugars found inside the fruit that is allowed to stay with the coffee beans longer.
Washed Process
This is the most common processing method. The ripe cherries are depulped, removing all the fruit layer. Then they are then fermented (either dry or in water) for 12-72 hours, which breaks down the mucilage remaining on the seed. They are then washed and agitated, leaving only the parchment, and dried for 5 – 15 days. They’re then dry-milled, removing the parchment from the seed.
This process results in a coffee that’s cleaner, brighter, and more acidic. The intrinsic flavors of the coffee beans are prominent, without the influence of sugars and compounds in the mucilage present in the natural or honey processes.
Honey Process
This process is similar to a washed process except for the intermediate step. After the cherries are depulped, the mucilage is left on the seeds, and they’re dried for 2-3 weeks in the sun.
Depending on the drying time, the process is called yellow, red or black honey process. Yellow has the shorted fermentation, and the beans produced are very similar to a washed process bean. Red is in between, and the beans will have more fruit flavor and sweetness, with a syrupy body. Black honey process beans ferment the longest, with more mucilage left on the bean during drying, resulting in a stronger fruity profile, intense sweetness, and a winey, creamy body (excellent for espresso, btw!).
Honey processing results in a balanced acidity with heavier body and evident sweetness, with a honey-like aroma. Kind of a pleasantly complex cross between a Natural and Washed coffee.
Wet Hulled Process
This process, also called semi-washed or Giling Basah, is typically used in humid climates like Indonesia where extended drying periods in the hot dry sun are difficuly. To speed up the drying process, the coffee cherries have their pulp removed as usual, a quick overnight ferment and wash, and a quick dry to around 50% moisture. They’re then sent a wet-huller, which removes the parchment from the seed with water and friction. The “naked” seeds are then spread out to dry to the standard 12% moisture, which takes much less time. All in all, it’s a month from harvest, vs a typical 2-3 months for other processes.
Flavors here are rich and earthy, with sweetness and acidity and full body. They’re often used in blends for body, but quality ones are delicious as single-origins. Our Bali Blue Moon is a favorite, with undertones of vanilla bean and cinnamon, a little bit chocolatey, a thick syrupy body, and lingering but not too earthy finish.
Anaerobic Process
This is a broad process term that encompasses a number of variations, but generally the idea is for coffee cherries to spend 1-12 days in an sealed bag or container without oxygen, with or without additives like yeast, bacteria, fruit, water or anything else. After fermenting is complete, the cherries are processed as naturals, washed or honeys.
Because of the time and commitment to detail and additional steps, anaerobic coffees are generally more expensive, akin to fine wines. Higher price, but an outstanding cup of coffee.
This fermentation process produces fruity coffee beans (since they are steeped in the cherry’s fruit juices), but also can have a range of additional flavors and aromas like pineapple, cherries or lemon due to additives used in the process. Generally, they taste creamier than regular coffee, but no acidity or bitterness. Which means you lose the flavor profiles of standard coffee, but the richer, fruitier tastes will be far more prevalent.
Carbonic Maceration Process
This is really a subset of the anaerobic process, where CO2 is pumped into the anaerobic tanks during fermentation of the cherries. It can produce coffees with intense flavor profiles, with boozy and cooked fruit flavors, or even banana, bubblegum or whiskey!
It’s not for everyone (farmers or coffee drinkers), but has been a way for coffee producers to differentiate their coffee from others.