Coffee Processing Explained

Coffee processing is a crucial step in transforming freshly harvested coffee cherries into the rich, aromatic beans we brew daily. The method used to process coffee can significantly influence its flavour, aroma, and overall quality. Understanding different coffee processing methods can enhance your appreciation of the diverse profiles and unique characteristics found in each cup.

At its core, coffee processing involves removing the outer layers of the coffee cherry to reveal the beans inside. However, how this is done can vary greatly, leading to a wide array of flavour profiles. From traditional methods to innovative techniques, each processing method imparts distinct qualities to the coffee.

Washed Processing

The washed coffee process, also known as the "wet process," is a coffee processing method that involves removing the outer fruit layer from the coffee bean before drying. This method is popular because it produces a clean, bright, and consistent flavour, allowing the natural qualities of the bean to shine without too much influence from the fruit. Here’s a breakdown of how it works:

The Process:

1. Harvesting: Ripe coffee cherries are picked, usually by hand to ensure quality.
2. Pulping: The cherries are immediately put through a machine that removes the outer skin and most of the pulp, leaving the beans covered with a sticky mucilage.
3. Fermentation: The beans are then placed in water-filled fermentation tanks for 12 to 48 hours. During this time, naturally occurring enzymes break down the mucilage.
4. Washing: After fermentation, the beans are rinsed thoroughly to remove any remaining pulp.
5. Drying: The clean beans are spread out on drying beds, patios, or mechanical dryers to reach an optimal moisture level of around 10-12%.

Flavour Profile

Washed coffees typically have a clean, bright acidity with a clearer representation of the bean’s inherent flavours. They are known for their clarity and complexity, often highlighting citrus, floral, or nutty notes. The absence of the fruit during drying means less sweetness and fruit-forward flavours than natural-processed coffees, but a more refined and consistent flavour.

Pros and Cons

• Pros: Consistent and clean flavour; brings out the natural characteristics of the bean and terroir; ideal for showcasing high-quality beans.
• Cons: Water-intensive, which can be a drawback in regions where water is scarce; requires careful monitoring during fermentation to prevent over-fermentation.

The washed process is especially popular in Central and South American countries, as well as East African countries, where coffee farmers often seek a refined and balanced profile in the cup.

Check out our STROUDIE BREW as a classic washed coffee 

Honey Processing 

Honey processing is a coffee processing method that is a middle ground between the natural and washed processes, blending aspects of both. It involves removing the outer skin of the coffee cherry but leaving varying amounts of the sticky mucilage (or “honey”) on the bean as it dries. This method was developed as a way to reduce water use while achieving flavours that balance the clean notes of washed coffees with the fruity sweetness of natural-processed coffees.

The Process:

1. Harvesting: Ripe coffee cherries are picked by hand to ensure quality.
2. Pulping: The cherries are de-pulped to remove the outer skin, but the mucilage layer remains partially intact.
3. Drying: The beans with mucilage are spread out on drying beds or patios and turned frequently to prevent fermentation from happening unevenly. The drying process can take longer than the washed method but less than the natural process.

The amount of mucilage left on the bean can be varied, which leads to different types of honey processing:

• White Honey: Little mucilage is left, resulting in a flavour closer to washed coffee.
• Yellow Honey: A moderate amount of mucilage is left, producing a balance of fruity and clean flavours.
• Red Honey: A larger amount of mucilage remains, often resulting in a sweeter, fruitier profile.
• Black Honey: Almost all the mucilage is left intact, with drying in partial shade to slow fermentation, creating intense fruitiness and sweetness.

Flavour Profile

Honey-processed coffees are known for their balanced flavours, often combining the acidity of washed coffees with the sweetness of natural-processed coffees. Depending on the amount of mucilage, they can have hints of fruit, honey, caramel, and syrupy textures, with varying levels of body and complexity.

Pros and Cons

• Pros: Reduces water usage compared to washed coffee; allows for unique and diverse flavours; good for climates where natural drying conditions can be controlled.
• Cons: More labour-intensive than other methods, requiring skilled monitoring to prevent uneven drying and over-fermentation; challenging in humid climates.

Honey processing is particularly popular in Costa Rica and other parts of Central America, where producers enjoy the control over flavour profiles without using large amounts of water.

Check out our VERENA BLASSER & HENRY GAIBOR as great examples of Honey Processing

Natural Processing

Natural processed coffee, also called "dry-processed" coffee, is a method of coffee processing that involves drying the coffee cherry with the fruit still intact around the bean. Here’s a breakdown of how it works and why it’s unique:

The Process:

1. Harvesting: Ripe coffee cherries are hand-picked.
2. Drying: Instead of removing the cherry’s pulp immediately (as in washed coffee processing), the entire fruit is spread out to dry on raised beds or patios.
3. Fermentation and Sun Exposure: Over several weeks, the cherries are left in the sun, turned frequently to ensure even drying, which allows the flavours from the fruit to infuse into the beans.
4. Removal of Fruit: Once the cherries are fully dried, the outer layers are removed mechanically to reveal the bean inside.

Flavour Profile

Natural processed coffees are known for their intense fruit flavours, such as berry and tropical notes, and often have a fuller body. The longer contact with the cherry’s pulp and sugars brings out sweet, fruity, and sometimes wine-like characteristics in the coffee. They can have a "wilder" flavour profile compared to washed coffees, which are often cleaner and brighter.

Pros and Cons

• Pros: Unique, bold flavours; fuller body; often a lower environmental impact since they require less water.
• Cons: Harder to control consistently due to fermentation risks; more labour-intensive, requiring skilled producers and ideal weather for drying.

Natural processed coffee is popular among specialty coffee enthusiasts who enjoy these complex, fruity notes, often found in coffees from regions like Ethiopia and Brazil, where the climate supports this drying method.

Check out our FLARE coffee as a classic example of Natural processing 

Experimental Processing

Experimental coffee processing refers to unconventional methods that go beyond the traditional washed, natural, and honey processes. These methods are designed to produce unique and complex flavours, often using fermentation techniques and creative drying methods. 

Common Experimental Processes

1. Anaerobic Fermentation:

   • Process: Coffee cherries or de-pulped beans are placed in sealed, oxygen-free tanks to ferment, either with or without the mucilage. This environment allows unique bacteria and yeasts to develop, resulting in distinctive flavours.
   • Flavour Profile: Anaerobic processing can create bold, intense flavours, often with notes of spices, tropical fruits, or a wine-like complexity.

2. Carbonic Maceration:

• Process: Inspired by winemaking, coffee cherries are placed in a sealed tank filled with carbon dioxide. This method limits oxygen, causing pressure changes that draw out new flavours and ferment the beans more slowly and evenly.

1. • Flavour Profile: Carbonic maceration can yield floral, fruity, and often layered flavours with a wine-like acidity and smooth body.

2. Yeast Inoculation:

   • Process: Specific strains of yeast are introduced to ferment the coffee, similar to how certain yeasts are added in brewing beer or making wine. The yeast adds controlled flavorus and affects the texture of the coffee.
   • Flavour Profile: This technique enhances fruity, floral, or even spicy notes depending on the yeast strain, offering unique consistency and complexity.

3. Lactic Fermentation:

   • Process: After depulping, coffee is fermented in an environment that encourages lactic acid-producing bacteria to thrive. This can be achieved by controlling the environment or adding lactic acid bacteria.
   • Flavour Profile: Often results in a creamy, yogurt-like acidity, with soft fruit notes and a fuller body.

4. Koji Processing:

   • Process: Inspired by Japanese culinary practices, this involves adding Aspergillus oryzae mold, commonly used in sake production, to break down sugars and release specific flavours.
   • Flavour Profile: This process can result in complex, umami-like flavours with earthy and savoury notes uncommon in traditional coffee.

Benefits and Challenges

• Benefits: These processes open up new flavour potentials and can yield exotic and rare taste experiences. They offer producers a way to stand out in the specialty coffee market.
• Challenges: Experimental processes are complex and require skilled monitoring. Small deviations can lead to overly fermented or off-flavours. Additionally, these processes can be time-intensive and require specific conditions, such as temperature control, anaerobic chambers, and specialized knowledge.

Overall Appeal

Experimental processing is often prized by coffee enthusiasts, as it brings out surprising, complex flavours and aromas, sometimes unlike traditional coffee profiles. These methods are typically applied to high-quality, specialty beans from innovative farms, making experimental coffees premium and often higher-priced.

Anaerobic processing can produce extraordinary flavour, ranging from fruity and floral to wine-like and spicy, by controlling the fermentation environment. The method of fermenting coffee beans creates unique and complex flavours. Here's a simple explanation:

1. Harvesting: Coffee cherries are picked from the coffee plant.
2. Pulping: The outer skin of the cherries is removed, leaving the beans with some of the mucilage (the sticky layer) still on them.
3. Fermentation: The beans are placed in sealed, oxygen-free containers (like tanks or bags) where they ferment without air. This is called anaerobic fermentation. Because there’s no oxygen, the fermentation process is different and can produce more intense and diverse flavours.
4. Drying: After fermentation, the beans are dried either in the sun or with machines.

Anaerobic processing often results in coffee with unique, complex flavour that can include fruity, floral, or wine-like notes. The lack of oxygen during fermentation can create a more controlled environment, allowing for a wider range of flavour profiles.

Check out our TIDE coffee a delicious anaerobic natural process.