For coffee lovers out there, fermented coffee has brought a revolution to your brewing techniques. Whether you prefer pour-over, AeroPress, or cold drip brewing, fermenting your coffee can open a new world of aromas, flavors, and coffee depth.
Now, what exactly is fermented coffee? How does it stand out from regular coffee? And why is coffee fermented the new craze nowadays? This guide has the answers for you!
What is Fermentation?
Fermentation is a biological process where bacteria and yeast break down starches and sugar into simpler substances.
Beer, for example, goes through fermentation, which gives beer its distinct flavor and taste. As for coffee, the fermentation process is no stranger to coffee, particularly coffee cherries. Fermentation can happen in many ways, and you can use different enzymes and catalysts to manipulate the fermentation process and achieve the desired result.
In short, fermentation is a chemical change that happens when you combine water and sugar together.
Coffee Vs. Fermentation
So, where does the fermentation of coffee come in?
During the initial stages prior to roasting, grounding, and brewing, fermenting coffee or rather, coffee cherries, is a crucial step to producing those lovely coffee beans. Once coffee cherries are plucked, separating the fruit husk from the beans is no simple matter. It’s not as easy as scraping the husk away.
This is where coffee fermentation comes in, and it can happen in two ways.
The first way involves leaving the cherries under the sun’s heat, where the fermentation takes place and softens the husk for easier separation.
The second way is submerging the coffee fruit in a water tank where the fermentation takes place over a short period.
As you can see, coffee fermentation isn’t a new concept since it occurs before the roasting process.
Fermented coffee; however, or cultured coffee undergoes a second fermentation process after the husk is removed and the fruit has been pulped.
That’s not all. Some ferment the coffee even after brewing. Using a culture starter (a mixture of yeast and bacteria), you let the coffee sit for days, similar to yogurt’s fermentation process. The result?
Types of Fermentation
You’re already familiar with the Kombucha fermentation, so let’s step into other fermentation types that make fermented coffee a unique brew.
Kefir – To ferment coffee with Kefir, cow’s or goat’s milk is inoculated with kefir grains. Since fermentation requires sugar for the process to happen, using milk that contains lactose which would make the perfect candidate.
Take note, though, that adding Kefir to your coffee cannot be done over high temperatures. High heat will destroy the culture starter or yeast and bacteria, which prevents fermentation from happening.
Kopi Luwak – Kopi Luwak or Civet coffee undergoes a unique coffee fermentation process commonly referred to as cat poop coffee.
Civet is a cross between a cat and a raccoon where its feces are used and collected for making coffee. The thing about Civets is that they only eat the best fruit thanks to its keen sense of smell.
This means a Civet would never pick bad fruit, and objectively speaking, the beans collected from a Civet are only the best or cream of the crop.
These beans undergo heavy sanitation (of course) and are roasted just like how all coffee beans go through.
How Does Fermentation Influence Coffee Quality?
There’s a broad range of different flavors one can produce through fermentation.
Fermentation can refine the sweetness, body, and acidity of the coffee, and even add a fruity note to it.
Take note, though, when coffee is poorly fermented, it can result in a moldy flavor, which ruins the flavors. This is why it’s crucial to monitor the process and adequately understand how fermentation works.
Time is a crucial factor, and under-fermented or over-fermented coffee can cause a loss of quality like the sweetness, acidity, and body. If fermentation is done right, you can bring out the coffee’s best characteristics and flavor. It’s how you let exotic coffee come into play and open a new world of flavor.
Humidity, for example, affects the coffee fermentation process and dictates what the best method would be. Wet processing can dry processing will produce different coffee bodies and results. This is to ensure the consistency of the beans’ quality, where things like temperature, moisture content, and even airflow all contribute to making high-quality coffee.
Process of Fermented Coffee
To understand how fermented coffee is made, we’ll go through the steps one by one in this section.
Step 1: Soaking
The coffee beans are soaked in water so that the microorganisms, which are responsible to ferment the beans, will have an easier time coming in contact with the beans.
Step 2: Inoculate the Beans
You’ll want to use 1+ types of yeast and bacteria for this step. Inoculating the soaked beans involves adding the bacteria and yeast in the form of a liquid starter solution (also known as SCOBY – Symbiotic Colony of Bacteria and Yeast).
Inoculation works the same way you age cheese, wherein using different microorganisms produce different types of cheese like camembert, cheddar, mozzarella, roquefort, etc.
For this step, you can use different kinds of starter solutions to ferment your coffee beans in various ways, resulting in different aroma and flavors.
Step 3: Wait for 24 to 48 Hours
The 3rd step is where the actual fermentation takes place.
You’ll have to let the beans sit for 1 to 2 days so that the yeast and bacteria can work their way into modifying the chemical composition of your beans.
This modification can produce an improvement in the flavor, aroma, body, and even the digestibility of the coffee.
Although it’s not as simple as just waiting and sitting around. You’ll also have to carefully monitor your beans and consider factors like temperature, time, airflow, light exposure, etc. These factors combined can make or break the quality of your coffee from the sweetness and aroma down to the color and shelf life.
Learning about the fermentation conditions takes time, and mostly through trial and error. You’re also free to do your own research and ask for advice from friends.
Just remember that fermenting is a delicate process. Soaking the beans in water compared to drying them under the sun can affect how the sugar is broken down, and most of all, the quality of your coffee.
Step 4: Washing & Drying
Once the beans have fermented, it has to undergo washing to remove any residues. It is then dried either under the sun or through a machine like a mechanical dryer.
The drying stage is vital to your bean’s health and quality. High moisture and high temperature can increase the risk of mold. What’s even more critical is to make sure that each bean is dried evenly.
Using a thermohygrometer can significantly help the drying stage to ensure quality monitoring. Another factor to note is the drying technology used like patios, mechanical dryers, plastic, or raised beds.
Among the four mentioned, raised beds provide the best even drying and allows proper airflow too.
Mechanical dryers might be efficient for handling large loads, but this usually results in uneven drying as well.
As for the other technologies mentioned, it’s mostly a problem with moisture, which can damage the bean’s shelf life and flavor.
Step 5: Roasting
Who doesn’t love a good roast?
Roasting is essential to your coffee quality because it’s responsible for bringing out the aroma and flavors trapped inside the green coffee beans.
Through extremely high temperatures, roasting produces a chemical process or change that can give your coffee a robust and rich body or a light, smooth one.
Knowing your roasts is vital to being a coffee manufacturer or producer, and it can take years to become a master at the art of roasting.
Here are 4 common kinds of roasts to take note of:
- Light Roast – Light roasts are light brown in color and don’t have a shiny, oily surface since these weren’t roasted long enough for the oils to break through. Light roasts are also for those who prefer milder coffee varieties.
- Medium Roast – Coming in with a medium brown color, medium roasts offer a stronger flavor and a more balanced acidity, aroma, and body.
- Medium-Dark Roast – Medium-dark roasts have a darker brown shade with a slight shine on the surface. It also gives a bittersweet aftertaste.
- Dark Roast – Dark roasts are also referred to as charred roasts due to their shiny, black color. In addition, they have significant amounts of a bitter taste.
Roasting oxidizes the compounds found inside the bean, so it’s important to pay careful attention to the type of roast you want.
Step 6: Grinding
Grinding depends on the method or technique you prefer to have your coffee. If you prefer pour-over, for example, you’ll need a coarser grind rather than a fine grind.
As a result, this will also be different if you choose to use an AeroPress or cold drip or press.
Benefits of Fermented Coffee
We’ve learned the steps on how to make fermented coffee, including the fermentation types and how it affects your coffee’s quality.
Is it really worth all the craze?
We can think of one reason why: its benefits. For serious hardcore coffee-lovers, fermenting opens a new world of possibilities for you to explore and experiment with!
Here’s a list of benefits to help you get started on why fermented coffee has become so popular.
Fermentation helps break down complex substances into simpler substances, making it easier for your body to handle the compounds in fermented coffee.
Compared to regular coffee, the compounds found when you ferment your coffee have lesser amounts.
This makes it easier for those with gastrointestinal discomfort like Irritable Bowel Syndrome, for example, to digest fermented coffee without experiencing irritation.
Enhanced Aroma and Taste
When you ferment brewed coffee, you’re also able to have more control on how to influence the taste and aroma. It’s not just simple water and sugar.
After all, fermenting coffee during the initial stages already influences the quality of your coffee.
Adding a second fermentation stage allows you to control specific parameters like the bitterness, acidity, and even add a more distinct caramel, chocolate, or fruity note.
Regular coffee has its own set of distinct tastes and body not to mention, using different techniques such as pour-over can bring out an even stronger body and taste.
With fermented coffee, it’s really a matter of how knowledgeable you are. The more experience you have working with fermenting your coffee, the more consistent high-quality you have.
Factors such as water pH level, brix, and even using distilled or mineral water can affect your coffee’s taste!
We mentioned earlier that you can choose a variety of liquid starter solutions to add to your brewed coffee. This doesn’t only influence the taste and aroma, but it also inhibits the growth of fungi.
As a result, fermented beans have fewer chances of spoiling and provide a safer, cleaner drinking experience.
Regular coffee, tea, wine, and certain foods contain tannins, which can turn your teeth yellow over extended periods of time.
Fermented coffee has reduced amounts of tannins, so you can be sure that your teeth will stay pretty white as it is.
Ready to brew your own fermented coffee? Don’t let a few technical details stop you from trying it out for yourself!
We hope this article was able to teach you everything there is to know about fermented coffee! If you’ve tried Civet coffee yourself or want to share your coffee experiences, let us know. How does this compare to nitro cold brewed coffee?
Lead marketer, brewer, dad, and husband. Pretty much an all-round awesome guy.