Fermented Coffee Beans:
What are They? Do They Taste Better?

Sourdough. Kombucha. Kefir. Kimchi. Tempeh.

It’s fair to say that fermented food and drinks are all the rage just now. But fermented coffee? Is it just a step too far?

Usually, coffee is prized for its freshness and bright, zesty flavors. But, this isn’t the usual flavor profile of something that has been fermented.

During processing, all coffee undergoes a small amount of fermentation regardless of whether it is wet, dry, or honey processed. It is this slight fermentation that creates the fruit and floral aromas and the complex sugars that add sweetness to our morning cup. 

But, specifically fermenting coffee beans can do so much more and can offer a completely different coffee experience with a whole raft of new flavors to enjoy.

So, if you’re already a fan of kefir and kombucha then fermented coffee could be your new caffeinated best friend. Or, if you’re skeptical about all things fermentation, trying a cup of joe from fermented beans could be the gateway to a life full of fermented goodness. 

The by-products of this metabolic process are what give fermented foods and drinks their distinctive flavors. These compounds include:

• Acetic acid like you find in vinegar
• Alcohols like ethanol which are found in beer/wine
• Gases like CO2 which make the bubbles in Champagne

This isn’t a new process. In fact, mankind has been using fermentation for thousands of years to preserve foods, ensuring they are safe to eat and drink, plus to add flavor.  

So, when it comes to fermented coffee this is simply coffee beans that have been put through the fermentation process, which seems simple enough. But all coffee undergoes some amount of fermentation during coffee processing. So we need to distinguish our fermented coffee from the regular type that undergoes a little bit of fermentation. 

Fermented coffee, sometimes called cultured coffee, is coffee that has undergone fermentation after processing and removal of the husk, but before roasting. So, green coffee beans are used.

By fermenting coffee at this stage, lots of new aromas and flavors develop which can be enjoyed after it has been roasted, ground, and brewed. Some will argue that this makes it the best coffee, far superior to regular coffee. Whilst others suggest these changes are “faults” and undesirable.

One thing is for certain: fermented coffee beans offer a unique coffee experience. 

Step 1: Bath Time

First up, the green beans need to be soaked in water. This makes it easier for the microorganisms that will do the hard work fermenting the coffee to come into contact with the beans. And, it provides a medium for the microorganisms to grow.  

Step 2: Innoculate 

Next, a starter solution is added to the soaking beans – this is just a liquid combination of bacteria and yeasts. These are the organisms that will actually ferment the coffee beans.

Depending on the desired style and coffee flavor, different bacteria and yeasts can be added. Each has slightly different characteristics and will yield different flavors in the finished coffee. 

Step 3: Coffee Fermentation Process

Now, it’s time to put your feet up and wait whilst the culture gets to work on the coffee beans. It can take 24-48 hours for fermentation to take place. During this time, the chemical make-up of the coffee beans is altered. The result is amazing flavors and aroma.

This is also the most technically challenging part of the process:

The culture needs specific temperature, light, exposure to air, and time to get the desired result. And it can be difficult to accurately control these elements whilst the cultured coffee undergoes fermentation. If it goes wrong, you will end up with vinegary-tasting coffee, which is less than ideal!

Finding the right balance for this experimentative coffee is usually through a process of trial and error. Although many specialty coffee producers do take a more systematic approach as there are cultures available with known properties.

Step 4: A Good Clean

Once the fermentation process has finished, the coffee beans need to be washed to ensure all the bacteria and yeasts are removed. Then they can be dried, either in the sun or by machine, before roasting. 

Ensuring they are thoroughly washed and dried is critical. Failure to do so will mean fermentation will keep taking place and all the hard work will be ruined. Plus, it prevents the fermented coffee beans from going moldy in storage before they are roasted.

Step 5: Time to Get Roasty

Roasting is where heat is applied to the green coffee beans, turning them into the brown beans we know and love. This stage is so important as the roast determines the coffee quality and flavor almost as much as the farming and processing combined.

During roasting, many of the organic compounds that give coffee beans their taste and aroma are oxidized. It also releases a lot of the oils stored within the beans which add flavor to the finished cup of joe.

In order to enjoy the full flavor of fermented coffee beans, it’s best not to have a roast any darker than medium. 

Well, Kopi Luwak beans are any type of coffee beans that have been collected from the feces of the Palm Civet cat in Indonesia. Hence its other name – cat poop coffee. The beans are washed, obviously, before being roasted and ground for making coffee. Many claim it is the best coffee for 2 reasons:

1. Palm Civets only eat the ripest coffee cherries – the ones with the best seeds 
2. The seeds undergo fermentation in the cat’s digestive tract, softening acidity and releasing more fruity flavors

Kopi Luwak was first started as a process in the 19th century when Indonesia was under Dutch rule. The plantation workers would collect the beans from the Civet droppings to make their own coffee. 

Is Kopi Luwak Good Quality Coffee?

Throughout the coffee industry, Kopi Luwak is viewed as more of a gimmick than a superior-tasting coffee. However, the lower acidity does lead to a “smoother” cup which, for some people, is an improvement. Although the flavor is also reduced. 

In 2012, Rocky Rhodes (yes, that is his real name) of the International Coffee Consulting Group tasted 4 coffees from the same farm in East Java. One was Luwak, and it scored 4 points below the best coffee on the SCAA scale. 

Now, 4 points lower out of 100 is hardly a damning review – and it’s unclear if Rhodes tasted blind. Then, to make matters worse, the farm fed cherries to caged cats. So, aside from the obvious animal rights issues, this also eliminates one of the important factors of Kopi Luwak – natural coffee fruit selection by the wild Civet.

So, it’s unclear if personal biases were at play here as, ultimately, not many people win if the global coffee industry say Kopi Luwak is the best tasting coffee in the world.

But, if Kopi Luwak sounds like your kind of thing, it’s worth trying for yourself rather than listening to the different coffee bodies who have their own motivations. The only thing that is certain is you should never drink Kopi Luwak made using caged civets.

This is coffee that has been brewed with regular coffee beans and then fermented by the addition of a specific culture used for making kombucha – hence the name.

Flavor-wise, Coffee Kombucha has a tangy taste and a slightly effervescent quality from the fermentation. It doesn’t get overly acidic and the flavor is loved by many. So it’s definitely worth a try if you’re looking for something a little different. 

Firstly, most coffee purists aren’t that interested in cultured coffee beans. So, without the demand, there’s not that much supply outside the specialty coffee market . 

Then, there’s the required investment from the coffee producers. As it takes quite a bit of trial and error to get the coffee fermentation process right, many just don’t see how it’s worth it.

And finally, with Kopi Luwak specifically, there is a level of uncertainty that comes from using wild animals. It’s difficult to get consistently high quality coffees at a certain volume when relying on the poop of wild Civet cats. This is where a market for caged Kopi Luwak comes from and it absolutely should be avoided due to the poor conditions for the animals. If you think the price is too good to be true, it probably is.

All that said, there are a couple of great-tasting choices you can try if you want to see what fermented coffee has to offer:

Volcanica Free Range Kopi Luwak Coffee

Cultured Coffee by EatCultured

EatCultured specializes in all things fermentation-based, focusing on overall gut health and the microbiome.

Their single-origin fermented coffee beans undergo the fermentation process to reduce both acidity and caffeine. This makes them more stomach-friendly if you are prone to digestive issues when drinking coffee.

As their primary goal is as a “health” brand as opposed to a quality coffee producer, if you’re looking for top-quality fermented coffee then the Kopi Luwak offers a better cup of joe.

The flavor and aroma of fermented coffee beans are like nothing you will have had before. And life is about trying new things, so why not give it a whirl.

There are several benefits to drinking fermented coffee. Firstly, it offers a more mellow coffee flavor with less bitter notes. So, if that’s what you’re looking for, you are sure to love it. Then, there’s the potential health benefits from drinking lower acidity coffee as it is kinder on the stomach, particularly for anyone who suffers from digestive issues or acid reflux.

One common misconception is that ferment coffee is packed full of probiotics like yogurt – the good bacteria that keep your stomach happy. But this is all lost during the roasting process.

So, is fermented coffee heading straight to the top of your shopping list?

Matt Woodburn-Simmonds

Matt's coffee obsession started in 2006 when working as a Barista. A tendency to turn up to work hungover kickstarted his coffee journey which quickly turned into a love affair. As he moved on to work as a Restaurant Manager and Sommelier, the obsession continued to grow. Now, his passion is helping others to enjoy better coffee at home.