Coffee Processing Methods Explained

When you buy a bag of specialty coffee, you may notice words such as washed,natural, honey or anaerobic on the label.

These terms describe how the coffee was processed after harvesting.

Coffee processing is one of the most important stages between the coffee farm and your cup. It can significantly influence sweetness, acidity, body, clarity and the flavours you experience when drinking the coffee.

Understanding processing methods can therefore help you choose coffee that matches your taste.

What Happens After Coffee Is Harvested?

Coffee grows inside a fruit commonly called a coffee cherry.

The coffee beans that we roast are actually seeds found inside the fruit.

After the cherries are harvested, the fruit must be removed and the seeds dried to a safe moisture level before the coffee can be stored, milled, roasted and brewed.

The method used to remove the fruit and dry the coffee is known as the processing method.

Different methods expose the coffee seeds to different conditions during drying and fermentation.

These differences can influence the final cup.

Washed Coffee

Washed processing is one of the most widely recognised methods in specialty coffee.

In a traditional washed process, ripe coffee cherries are harvested and the outer fruit is removed using a pulping system.

The coffee is then fermented or otherwise processed to remove remaining mucilage before being washed and dried.

The coffee is carefully dried until it reaches an appropriate moisture level for storage and milling.

Because much of the fruit is removed before drying, washed coffees are often associated with clean and clearly defined flavour characteristics.

What Does Washed Coffee Taste Like?

Washed coffees can display pronounced acidity, clarity and origin character.

Depending on the coffee, you may experience flavours such as citrus, berries, floral notes, black tea, stone fruit or chocolate.

Kenyan washed coffees are particularly well known for their bright acidity and distinctive fruit characteristics.

However, processing is only one factor.

The final flavour also depends on variety, growing conditions, harvesting, drying, roasting and brewing.

Natural Coffee Processing

Natural processing is one of the oldest coffee processing methods.

In natural processing, the coffee cherries are dried with much of the fruit still surrounding the seed.

The cherries are spread out on drying beds, patios or other suitable surfaces and turned regularly to encourage even drying.

Once the coffee has reached the appropriate moisture level, the dried fruit is removed during milling.

What Does Natural Coffee Taste Like?

Naturally processed coffee can have intense fruit character and sweetness.

You may encounter descriptions such as berries, tropical fruit, wine-like flavours, dried fruit or fermented fruit.

Natural coffees can also have greater body than some washed coffees.

The exact result depends on the coffee, drying conditions, fermentation and processing quality.

A poorly managed natural process can produce unwanted fermented or defective flavours, while a carefully processed natural coffee can be remarkably complex.

Honey Processing

Honey processing is particularly associated with coffee-producing countries where the method has been developed extensively.

Despite its name, honey processing does not involve adding honey to the coffee.

Instead, the coffee cherry is pulped while some of the sticky mucilage remains attached to the coffee seed during drying.

The amount of mucilage left on the coffee can vary.

Different honey processing styles may therefore produce different levels of sweetness, body and fruit character.

What Does Honey Processed Coffee Taste Like?

Honey processed coffees can sit somewhere between washed and natural profiles, depending on how they are processed.

They may combine clean acidity with greater sweetness and body.

You may encounter characteristics such as caramel, fruit, brown sugar, honey-like sweetness and chocolate.

Again, these are sensory descriptions rather than added flavours.

Anaerobic Coffee Processing

Anaerobic processing has become increasingly popular within specialty coffee.

The word anaerobic refers to an environment with limited or no oxygen.

In some anaerobic processing methods, coffee cherries or pulped coffee are placed inside controlled fermentation tanks or sealed containers.

Fermentation is carefully managed for a specific period before the coffee is dried.

The exact process varies significantly from producer to producer.

What Does Anaerobic Coffee Taste Like?

Anaerobic coffees can display highly distinctive flavour characteristics.

Depending on the process, you may experience intense fruit, wine-like acidity, tropical fruit, spice, chocolate or unusual aromatic characteristics.

Some anaerobic coffees can be very expressive.

Others may be more subtle.

Because anaerobic processing can vary considerably, it is important to read the information provided by the producer or roaster.

Fermentation and Coffee

Fermentation occurs naturally during several coffee processing methods.

Microorganisms interact with sugars and other compounds in the coffee environment, creating chemical changes that can influence flavour.

Fermentation is not automatically good or bad.

Controlled fermentation can contribute desirable complexity.

Poorly controlled fermentation can create unpleasant flavours.

This is why careful monitoring is important during processing.

How Processing Changes Coffee Flavour

Processing can influence several characteristics of the final cup.

Washed coffees are often associated with clarity, acidity and clean flavour.

Natural coffees can have greater fruit intensity, sweetness and body.

Honey processed coffees can offer a balance of sweetness, fruit and clarity.

Anaerobic and other experimental processes can create unusual and highly expressive flavours.

These are general tendencies rather than rules.

The same processing method can produce very different coffees depending on the producer, variety, climate and drying conditions.

Which Processing Method Is Best?

There is no universally best processing method.

The right method depends on the coffee and the desired result.

A producer may choose a particular process to preserve certain characteristics of the coffee or create a specific sensory profile.

For example, a high-quality coffee with excellent acidity may be processed in a way that preserves clarity.

Another coffee may be processed naturally to emphasise fruit sweetness and body.

Processing is therefore a tool used to develop and preserve coffee quality.

Washed vs Natural Coffee

If you prefer clean, bright and transparent coffee, washed processing may be a good place to start.

If you enjoy fruit-forward, sweet and full-bodied coffee, natural processing may be more appealing.

If you want something between the two, honey processing can be interesting.

If you enjoy experimental and unusual flavours, anaerobic coffees can provide a very different experience.

The best approach is to taste them yourself.

Coffee Processing in Kenya

Kenya has a long history of washed coffee processing and is particularly known for coffees that display bright acidity, fruit character and clarity.

Kenyan coffee processing has played an important role in developing the country's reputation within the specialty coffee industry.

At the same time, Kenyan producers are exploring new processing approaches and experimenting with different fermentation and drying techniques.

These developments are creating new opportunities for Kenyan coffee to express different flavour profiles.

Why Coffee Drinkers Should Care About Processing

Processing information can help you predict what kind of coffee experience you may have.

If you know that a coffee is naturally processed, you may expect greater fruit character.

If it is washed, you may expect greater clarity.

If it is anaerobically processed, you may encounter more unusual flavours.

This makes processing information useful when selecting coffee.

It also helps you understand the work involved in transforming a coffee cherry into the roasted beans you use at home.

Processing Is Only One Part of the Story

It is important not to judge coffee entirely by its processing method.

Two washed coffees can taste completely different.

Two natural coffees can also taste completely different.

The final cup is influenced by many factors, including coffee variety, altitude, soil, climate, harvesting, processing, drying, storage, roasting and brewing.

Think of processing as one important chapter in a much larger story.

How to Compare Processing Methods at Home

One of the best ways to understand processing is to taste different coffees side by side.

Choose a washed coffee and a natural coffee from similar roast levels.

Brew them using the same method and recipe.

Taste them while they are hot and continue tasting as they cool.

Pay attention to acidity, sweetness, body, fruit character, aroma and aftertaste.

Then try a honey or anaerobic coffee.

The differences can be surprisingly noticeable.

Final Thoughts

Coffee processing has a profound influence on the coffee we drink.

Washed processing can highlight clarity and acidity.

Natural processing can emphasise fruit, sweetness and body.

Honey processing can create a balance between different characteristics.

Anaerobic and experimental processing can produce unusual and highly expressive coffees.

There is no single best method.

The most important thing is careful processing that protects the quality of the coffee and produces a clean, enjoyable cup.

The next time you buy specialty coffee, look at the processing method on the bag.

It may give you an important clue about what is waiting inside your cup.