What is the Anaerobic Coffee Process?

As coffee enthusiasts, we're always looking for new, unique flavors to elevate our daily coffee cup.

One such innovation in coffee processing is the anaerobic coffee process, which has gained much attention recently.

But what exactly is this method, and how does it impact the taste of our beloved coffee beans?

In this article, we'll dive into the world of anaerobic coffee processing, explore its differences from other coffee processing methods, and discover what makes it such an intriguing option for the coffee enthusiast.

What we'll cover:

coffee drying on racks outside

Origins of the Anaerobic Coffee Process

The anaerobic coffee process is traced back to Central and South America, where innovative coffee producers experimented with fermentation techniques to create unique and differentiated coffee profiles.

As a relatively recent development in the world of specialty coffee, the anaerobic process is influenced by the wine industry, which has long employed anaerobic fermentation in its production.

In their quest for new and exciting flavors, coffee producers have drawn inspiration from the success of natural and washed processing methods, utilizing controlled fermentation environments to enhance the flavor characteristics of their beans.

The result is a coffee process that combines tradition, science, and innovation to produce exceptional coffees that have captured the attention and curiosity of the global coffee community.

What is Anaerobic Fermentation in Coffee Production?

Anaerobic fermentation is a coffee processing method that occurs in an oxygen-deprived environment.

This method involves placing the coffee cherries or beans into sealed tanks, containers, or bags with limited or no oxygen exposure.

The lack of oxygen forces the microorganisms, mainly yeasts and lactic acid bacteria, to break down the sugars in the coffee beans through fermentation without oxygen.

This process produces various organic acids, carbon dioxide, and other flavor compounds that contribute to the coffee's unique taste and aroma profile.

Anaerobic fermentation can be applied to both washed and natural coffee processing methods.

In washed anaerobic processing, the coffee cherries are de-pulped before fermentation. In contrast, in the natural anaerobic process, the whole cherries ferment without removing the fruit's pulp.

The main difference between these two methods lies in the flavor profile, with washed anaerobic coffees tending to be cleaner and more focused.

Natural anaerobic coffees often exhibit more intense, fruit-forward flavors.

Double Anaerobic Fermentation: A Novel Approach

Double anaerobic fermentation is an innovative coffee processing method involving two stages of anaerobic fermentation.

This technique aims to further enhance the complexity and depth of flavor in the final coffee product.

In the first stage, whole coffee cherries are placed in an oxygen-deprived environment.

This environment usually sealed tanks or bags to initiate natural anaerobic fermentation.

This stage can last from a few days to a couple of weeks, depending on the producer's preference and desired flavor outcome.

The whole cherries ferment, and the natural sugars in the fruit break down, resulting in an array of flavor compounds that permeate the beans.

Once the initial fermentation is complete, the cherries are de-pulped, and the beans proceed to the second anaerobic fermentation stage.

The beans, now without the fruit pulp, are placed back into an oxygen-deprived environment for another round of fermentation.

This second stage allows the beans to develop their flavor profile further and accentuate the unique characteristics imparted by the first fermentation stage.

The double anaerobic fermentation process demands meticulous attention to detail, as temperature, fermentation time, and moisture content can significantly impact the final product.

The result is a coffee with an incredibly distinctive taste, often boasting intense fruitiness, a wine-like acidity, and a nuanced complexity that sets it apart from conventionally processed coffees.

colorful coffee fruit being processed

Anaerobic Natural vs. Washed Anaerobic Coffee

When discussing anaerobic coffee processing, it's essential to understand the difference between anaerobic natural and washed anaerobic methods.

Both techniques utilize oxygen-deprived environments to ferment the coffee beans.

Still, they differ in the stage at which fermentation occurs and the resulting flavor profiles.

In the anaerobic natural process, whole coffee cherries are placed in a sealed, oxygen-deprived environment after harvest.

The cherries ferment with the fruit pulp still intact, developing bold, fruity flavors and a heavy body in the final cup.

This method emphasizes the influence of the coffee fruit on the beans' taste.

It can result in various flavor profiles, from tropical fruit notes to wine-like qualities.

On the other hand, washed anaerobic coffee undergoes an initial step of de-pulping before fermentation.

Once the cherries have been de-pulped and the beans are separated from the fruit, they are placed in a sealed, oxygen-free environment to ferment.

This approach produces a cleaner, more refined taste than the anaerobic natural process coffee.

Washed anaerobic coffee typically features a brighter acidity, floral or fruity notes, and a lighter body.

Both anaerobic natural and washed anaerobic coffees can offer extraordinary taste experiences.

The choice between the two largely depends on personal preference and the desired flavor profile in the final cup.

It's worth exploring both methods to discover the unique qualities each brings to the coffee world.

The Impact of Anaerobic Fermentation on Coffee Taste

Anaerobic fermentation has a significant effect on the taste of coffee.

Oxygen exposure is limited during fermentation, so the beans develop distinctive flavor profiles that set them apart from their conventionally processed counterparts.

The microorganisms responsible for fermentation in an oxygen-deprived environment produce a range of organic acids and other compounds that contribute to the coffee's unique characteristics.

Generally, anaerobically fermented coffees tend to have more intense, complex, and exotic flavors.

They often exhibit pronounced fruity, floral, or wine-like notes with a rich mouthfeel and a lingering aftertaste.

The specific flavor profile varies depending on the coffee variety, origin, and the specific anaerobic processing method used—whether it's anaerobic natural or washed anaerobic.

Anaerobic natural coffees often showcase bold, fruity flavors with a heavier body and a syrupy mouthfeel.

The taste can range from tropical fruit notes like pineapple or mango to wine-like qualities reminiscent of a fine red or white wine.

In contrast, washed, anaerobic coffees tend to have a cleaner, more refined taste.

The flavors are often floral or fruity, with a lighter body and sparkling acidity.

Compared to anaerobic natural coffees, the intensity of the flavors may be slightly subdued.

Still, the washed anaerobic process highlights the coffee's innate qualities and terroir.

It's essential to remember that taste preferences are subjective, and the best way to appreciate the impact of anaerobic fermentation on coffee is to try these unique beans for yourself.

You might discover a new favorite that challenges your preconceptions of what coffee can taste like.

How is Anaerobic Coffee Prepared?

Preparing anaerobic coffee involves a meticulous process broken down into several steps, each designed to harness the unique flavors the anaerobic fermentation method imparts.

Here's an overview of how anaerobic coffee is typically prepared, from the farm to your cup:

Harvesting: Carefully handpicking the coffee cherries when they reach optimal ripeness ensures the highest quality beans for the anaerobic process.

Fermentation: This process involves placing the cherries into sealed, airtight containers or fermentation tanks, with or without water, depending on whether it's an anaerobic natural or washed anaerobic process. Oxygen is either purged or limited within the container, creating an anaerobic environment that promotes the growth of specific microorganisms responsible for fermentation. The fermentation period can range from a few days to several weeks, depending on the desired flavor profile.

Monitoring: Throughout the fermentation process, the coffee producers closely monitor the temperature, pH, and other factors within the containers to ensure ideal conditions for the development of complex flavors. Producers make adjustments as needed to maintain the optimal environment for anaerobic fermentation.

Drying: The coffee beans are removed from the containers once they reach the desired fermentation level. The natural anaerobic process involves drying the cherries with intact fruit on raised beds or patios. The washed anaerobic process uses de-pulped cherries, rinsing the beans before being spread out to dry.

Hulling and sorting: This process occurs after the beans have reached the proper moisture content to remove the parchment layer. The producer then sorts the beans by size, density, and color to ensure a uniform, high-quality batch.

Roasting: The roast process applied to green coffee beans brings out the unique flavors developed during anaerobic fermentation. The roasting profile may vary depending on the specific characteristics of the beans and the desired flavor outcome.

Brewing: Finally, the roasted beans are ground and brewed to enjoy the exquisite flavors of anaerobic coffee. Experimenting with different brewing methods, grind sizes, and water-to-coffee ratios can further enhance the tasting experience and allow you to appreciate the nuances of these distinctive beans.

Is Anaerobic Coffee Better?

Whether anaerobic coffee is better than other types of coffee is subjective and largely depends on individual preferences.

What might be considered better to one person could be less appealing to another.

That said, several factors make anaerobic coffee stand out from its counterparts:

Unique flavor profiles: The anaerobic fermentation process can result in a wide array of intriguing and complex flavor profiles. This processing method offers a distinctive tasting experience not found in more traditional coffee processing methods. Some people appreciate these unconventional flavors, while others might prefer a more classic coffee taste.

Experimentation and innovation: Anaerobic coffee production often involves a high level of experimentation and innovation on the part of the coffee producers. This spirit of curiosity and creativity can lead to developing novel flavors and techniques that push the boundaries of coffee processing and challenge our understanding of what coffee can be.

Limited availability: Due to the precise and labor-intensive nature of the anaerobic fermentation process, anaerobic coffee tends to be produced in smaller quantities than other processing methods. This limited availability can make these beans more sought after and highly prized among coffee enthusiasts.

Ultimately, the "betterness" of anaerobic coffee comes down to personal taste and preference.

It's essential to approach these unique beans with an open mind and a willingness to explore new flavors.

For coffee lovers who enjoy experimenting with different taste profiles and appreciate the artistry behind coffee processing, anaerobic coffee may become your new favorite.


In the ever-evolving world of coffee, the anaerobic coffee process has emerged as an innovative and captivating method that pushes the boundaries of flavor and technique.

With its unique fermentation approach, this process can yield atypical, distinctive taste profiles compared to other processing methods.

While it's essential to recognize that personal preferences play a significant role in determining the appeal of anaerobic coffee, there's no denying the excitement and curiosity it generates among coffee enthusiasts.

So, whether you're a seasoned coffee enthusiast or just beginning your journey into specialty coffee, anaerobic coffee is worth exploring.

Keep an open mind, savor the exceptional flavors, and appreciate the artistry and passion behind this captivating coffee process.

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