Know Your Coffee: Coffee Processing 101

What’s on the label of your favourite coffee? Along with the origin, roast profile, and those useful tasting notes, coffee processing methods are crucial in forming the bean’s final flavour profile. They matter because they greatly affect your everyday brew! Here’s why.

In order to understand coffee processing, we first have to brush up on the coffee bean’s anatomy. The widely popular beverage we know and love comes from roasted coffee beans, and these beans are actually seeds of a fruit known as the coffee cherry.

The coffee cherry is composed of the following:

  • Skin, which surrounds the fruit.

  • Pulp, a fleshy layer that can be found beneath the fruit’s skin.

  • Mucilage, which is the inner layer of the pulp.

  • Parchment, a paper-like hull that envelops the seed.

  • Seed, in its purest form before it’s roasted, ground, and brewed!

Parts of the coffee cherry

We can think of processing as the extraction of the green coffee seed (or bean) from the coffee cherry. This means that the skin, pulp, mucilage, and parchment have to be removed in order to get to the seed. This is how coffee is processed in its most basic form, and there are many ways to go about this. How a farmer or producer chooses to process the coffee they have has a profound impact on how the coffee tastes once it is brewed. Let’s take a look at the different coffee processing methods below:

Common Coffee Processing Methods

Washed Process
Also known as Fully Washed, Wet Process, Parchment-dried

Developed in the Caribbean in the 1850s, this method became popular in Central America due to the higher volumes of coffee produced. It's a widely popular processing method due to its consistent results. In the washed process, coffee cherries are pulped and fermented in water to remove the skin, pulp, and mucilage. The beans are then dried on parchment, prior to dry milling and selling.

Flavours to expect: Floral, Bright, Citrusy, Clean

Natural Process
Also known as Dry Processed, Fruit-dried

This is the oldest form of coffee processing, traditionally used in Ethiopia and in Yemen. In this process, whole coffee cherries are laid on patios or mats, where they dry under the heat of the sun. This method gained popularity in coffee-growing sites with limited access to water, and was considered a poor choice for flavour due to its tendency for inconsistency and over-fermentation.

Nowadays, producers experiment with the natural process to give coffees an intense, funky, fruited flavour profile.

Flavours to expect: Fruity, Winey, Fermented

Honey Process / Pulp Natural
Also known as Mucilage-dried

This technique hails from Brazil, where it was referred to as ‘pseudo-natural’ processing. In this processing method, producers sort and depulp coffee, leaving the seeds in their mucilage to dry on a flat surface.

In 2008, an earthquake left washing stations in Costa Rica without water, driving coffee producers to explore a water-free alternative based on the Pulp Natural method, which they coined the “Honey Process”.

Many say that the Honey Process can mimic a Washed profile or a Natural profile, and this is achieved through differences in retained mucilage, drying time, or level of shade. White, Yellow, Red, and Black Honey processes are just a few of these subcategories.

Flavours to expect: Fruity, but also a large range of flavours

Other Processing Methods

Wet Hulled
Also known as Giling Basah, Seed-dried

Uncommon everywhere else, but it is the de facto processing method in Indonesia.

Much like Washed and Honey processes, the wet hulled method starts with removing the cherry’s pulp, while fermentation and mucilage removal is optional. While other processing methods include a drying on parchment step, the wet hulled process involves the drying of the bare seed. With a quicker drying time, this allows farmers to sell the product faster, but increases the risk of the seed absorbing not-so-palatable flavours.

Flavours to expect: Musty, Earthy, Herb-like, Chocolatey, Full-bodied

Anaerobic Fermentation
A highly-controlled, scientific way of extending the fermentation process.

Coffee is pulped and then placed in an airtight tank with a one-way valve. The anaerobic fermentation style takes longer than the traditional Washed style fermentation of 12-36 hours. Due to the lack of oxygen, a limited set of microbes affect the chemical reactions that take place, resulting in incredibly precise and identifiable flavour profiles.

Flavours to expect: Unique and distinct flavours such as bubblegum or whiskey

Carbonic Maceration
A technique adapted from wine-making where whole grapes are fermented instead of crushed.

Carbonic Maceration is similar to Anaerobic Fermentation, except that the cherries are placed inside airtight tanks without depulping. In addition, the chamber is flooded with carbon dioxide, which allows an extended fermentation time that can run from days to even weeks.

Flavours to expect: Unique and distinct flavours such as bubblegum or whiskey

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Coffee processing is rarely a talking point in shops or coffee websites, but it is, nevertheless, an integral part of crafting the coffee bean’s flavour and character. We don’t think there is a ‘best method’they’re all different expressions that unlock (or enhance!) the flavour potential of coffee. Still, the next time you pick up a bag of Honey Processed Costa Rican or some Natural Ethiopian capsules, you'll hopefully have an idea of what to look forward to!

Words by Jon Choi @theheadbean

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