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Naturally or artificially, fermented coffee brings out the best flavors, texture, aromas, and body when done correctly.
The taste exceeds every expectation of a coffee snob. It doesn’t change the taste but enhances its flavor profile and depth.
Coffee, when fermented, both naturally and artificially, makes the most-tranquilizing tasting beverage. It’s not difficult to brew fermented coffee, but it does ask for dedication, and most importantly, patience.
You can either ferment the coffee beans or ferment the beverages or even both, but doing it correctly and accurately is essential to avoid over or under-fermentation. All-in-all it brings out the natural richness of coffee beans and their undertones.
This article will give you a detailed tour of fermented coffee and how it’s done!
What is fermented coffee?
When you allow coffee to soak in water, sugar, healthy yeast, and bacteria culture, coffee beans’ complex sugar and starch break into smaller substances. The result of this process is called fermented coffee.
When these molecules break down, they release the fruity undertones on the surface and put forth the best flavors out in the beans.
It’s pretty simple to ferment coffee. It would help if you had coffee beans, water, and SCOBY.
SCOBY is a culture of bacteria and yeast together. It stands for a symbiotic colony of bacteria and yeast.
In a more straightforward definition, you soak the coffee beans in water and later add sugar+SCOBY for the fermentation process.
Artificially, it takes 1-2 days for the culture to break down the molecules completely. This culture period is significant for you to look out for.
You don’t simply sit when the beans are fermenting; you need to pay attention to the culture and keep it in the proper condition, temperature, climate, environment, etc. Later on, when the beans are appropriately fermented, they are dried well, roasted, and ground.
When you brew a fermented coffee, you will be surprised with the natural sweet undertones, full-body, less acidity, and fruity hints of the broken substances.
Coffee beans can go through four fermenting stages.
- The first one is natural fermentation which we’ll discuss later on.
- The second is fermenting the coffee beans artificially to remove mucilage,
- the third stage is fermenting the beans before roasting
- And the fourth optional stage is fermenting after the beverage is prepared. All these stages enhance the character of the coffee.
What does fermentation mean?
Fermentation is a natural process that involves water and sugar for starch/complex carbs to break down into smaller molecules. Fermentation can be performed artificially with catalysts and enzymes.
It’s a chemical change to digest food within simpler molecules like alcohol and acids for easy digestion and preservation.
The best examples to better explain fermentation are beer, cheese, yogurt, wine, kimchi. All these beverages and foods are stored in culture to result in a better food product.
These products are cultured with certain natural/artificial bacterias and yeasts to result in something better, more tasteful, and exotic.
Natural fermentation occurs to preserve food for longer. The alcohol (significantly less quantity) and the acids protect and preserve the food.
Why do we ferment coffee or foods?
- When we ferment food, we are adding healthy bacterias and yeast to our food. These bacteria protect our gut and food pipe.
- Fermentation keeps the food fresh for longer.
- It brings out the best flavors.
- Fermented food/coffee is rich in prebiotic bacterias which further protects your gut.
- Fermentation digests the food for you into a simpler substance. So, it’s easier to digest fermented food.
Is all coffee fermented?
Naturally, yes. Coffee beans ferment themselves because fermentation occurs when there are sugar and water together.
Coffee has it both in abundance, but picking out the right stage to pluck those cherries and de-pulp them off the husk is crucial because fermentation can override the cherries in no time.
Artificially, also yes. Coffee producers either dry ferment the coffee cherries or wet-process them (We’ll discuss this broadly later).
Coffee producers artificially ferment coffee to remove the mucilage layer and the impossible-to-remove husk.
Please note: It’s not as easy to remove proactive layers of the cherry. The mucilage layer is tough to skin-off the coffee beans, and it holds a lot of moisture that can ruin the beans if not removed at the right time.
Thus coffee producers, after de-pulping, ferment these cherries to remove the mucilage.
Fermentation breaks the mucilage layer and folds out the coffee beans. So yes, every coffee goes through both natural and artificial fermentation.
Yet another fermentation stage occurs artificially when the cherry is de-pulped and is taken out of the parchment layer. These coffee beans are again put in SCOBY, sugar, and water to extract flavors!
There’s a fourth optional artificial fermentation of brewed coffee that we’ll discuss further.
How long does it take to ferment coffee?
After plantation, coffee plants start to blossom fruits and thereby cherries after 4-5 years. The cherries are usually green when first visible but change their color as they ripen. Cherries ripen in about eight months, and that’s when cultivators harvest these cherries.
Coffee producers/cultivators may or may not allow natural fermentation because it can over-ferment many cherries. Fermentation does extract many fruitful tastes in the cherry, but it can also over-ferment it and sour it down.
After hand-picking the best cherries, the farmers put them in a big water tank for fermentation. Low-density cherries float out, and good cherries sink. It usually takes 8-36 hours for fermentation.
Fermentation successfully degenerates the mucilage and hardens the parchment. It is usually confirmed by feeling the stiff parchment at the surface of the coffee beans. It indicates the process is finished.
Third fermentation in SCOBY should be done for 1-2 days, not more, but under strict observation. If you perform it manually, you will need to do many trials and errors before stumbling on fermentation’s correct personalized process.
How is fermented coffee made?
- The first type is when it’s done naturally.
- The farmers handle the second fermentation to remove the mucilage.
- The third and fourth fermentation is in your hand. You can buy a third-stage fermented coffee from a cafe, or you can ferment it yourself.
How to ferment your coffee beans at home?
Coffee beans delivered to you do not have mucilage or parchment as the upper layer. So, you are directly fermenting the inside content of your coffee beans.
The second cannot get to the inside content of the beans; it only ever removes the mucilage and hardens the parchment.
When you ferment, you are fermenting the complex carbs present inside the beans that you will later grind and brew.
The very first step is to gather water for the fermentation to begin. Fermentation occurs when there is ample water and sugar together. So, the first step is soaking coffee beans in the water.
Soaking the beans allows them to be more flexible for the bacterias and microorganisms to contact the beans more readily. Once the coffee has been soaked completely, you can add SCOBY.
SCOBY stands for a symbiotic colony of bacteria and yeasts. It has more than 1-type of bacteria and yeasts. Reports even confirm that there are almost 50 yeasts and bacterias present while the coffee is being fermented.
Please note: You don’t want to introduce too much water to the coffee beans.
Make sure the water is only 1-2 inches above the batch of coffee beans. Remove the beans that float up at the top surface. However, this is rare because the second fermentation makes sure to remove low-density beans from the batch.
Inoculating is introducing the yeast culture in the culture medium. In this case, the culture medium is soaked coffee, and you will be inoculating SCOBY- bacteria and yeast culture in it.
You can use different microorganism cultures. You can use a previous batch of fermented coffee as well. Make sure it is not more than a day old.
A previous culture or fermented beverage has many bacterias and yeasts inside it, enough for a new process. So, you can always use it to inoculate your coffee beans.
If you don’t have a previous batch, you can prepare a new culture of non-pathogenic, non-toxic, aromatic yeast and Lacto bacterias.
Aromatic yeasts have been reported to add more flavor to your coffee beans. You can even use a fermented coffee beverage as a starter culture.
Once the medium has been prepared, and the coffee beans are completely soaked and inoculated, you need to wait for it to ferment properly.
The waiting time is when the actual process begins, and microorganisms start to cut down the complex sugar into smaller molecules. These smaller molecules are usually alcohol, acids, ethanol, etc.
You will need to wait for a day or two for your coffee beans to ferment correctly. This phase is very crucial, and you must monitor it closely. A single lousy element can ruin your complete batch.
Different cultures and bacteria/yeast types will demand a distinct environment to flourish. Some might need a warm heated environment, and others might need a cold temperature to sustain, just like curd ferments beautifully in summers.
For instance, Kefir cannot create a starter culture at high temperatures; it demands a cold place to process.
Ideally, farmers suggest 20 degrees celsius temperature for 24-44 hours. High temperatures can ferment the beans faster, giving birth to many errors. Hence, slow and steady is the key to your culture.
A very famous yeast named saccharomyces cerevisiae has resulted in a very profound coffee with fruity flavors, full body, and smooth textures.
You can buy a culture from kombucha manufacturers, or you can buy SCOBY from the biologist, or you can prepare your own in about four-five weeks.
Drying is crucial to remove the moisture away from the coffee beans. Water can mold your coffee beans and destroy their flavors. Thus, it’s vital to dry them evenly and moderately. Too much heat or too little time can ruin your batch.
You must make sure to provide moderate heat for a reasonable period for the coffee beans to dry peacefully and equally. Drying them equally is essential for more consistent flavor and quality.
Drying can be done in several ways: natural drying or mechanical drying. Mechanical drying usually uses big machinery to dry a bigger batch. For a household batch, you can dry them on raised beds under sunlight.
Machinery drying leads to uneven coffee beans, and thus, natural drying is often preferred for high-quality beans.
To sun-dry, you can spread your beans on raised beds. Make sure no bean overlaps the other and has enough space for airflow. Monitor your beans closely and observe if they completely let go of the moisture or not. You can break or cut a coffee bean to check the insides.
Once the color dries out and it feels hard, you can move onto roasting.
Roasting is the first step to brewing your coffee. Roasting extracts the natural flavors and essential oils of the coffee beans hidden inside. Although it’s not rocket science to roast coffee beans, the minute you lose patience, you might end up burning them.
You can roast your coffee in a big roastery, bake the beans in the oven, or do it the traditional way with the stove.
Honestly, traditionally hand roasting the coffee beans is more efficient and yields better results.
To get the best result, you must roast the beans for an extended period on low flames. High flames will only burn the beans’ walls without even getting inside the coffee beans. So, the key is to slow roast them.
Roasting includes heat, and thus, it’s a chemical change that takes place inside the coffee beans. Coffee beans start to structurally change from soft to crunchy.
You will also notice a color change in your coffee beans. This color depicts the stage of roasting you are at.
Coffee beans are either roasted light, medium, medium-dark, or darkest. Please note: All must be done on low flame.
Light roast: Light roast is done for a shorter period, and it doesn’t extract many coffee flavors or oils, if at all. Usually, a light roast is preferred for no particular brewing method.
Medium roast: Medium roast is crunchy and brown. It’s roasted for a reasonable period. Medium roast extracts enough flavors and oils but not all of them. It’s suitable for coffee that is steep for a more extended period.
Dark-medium: One of the best roasts out there is dark-medium. It extracts all the flavors and oils hidden inside the coffee beans. It has a dark chocolate brown color and is very crunchy.
Dark-medium doesn’t give away a burnt taste, and neither does it look burnt. It has an exotic color and flavor profile. You won’t witness oils outside the beans either; they are extracted but come out when you grind the beans.
Darkest roast: It’s close to burnt, but when monitored closely, you can prepare a robust coffee with deep crema out of the darkest roast.
Dark roasts are roasted for so long that the oils ooze out on the surface of the coffee beans. They are visible at the surface and account for an outstanding crema.
Coffee beans’ oil makes crema. But these beans can be dangerous for your super-automatic espresso machines.
Roasted beans have an expiry of 20-30 days, don’t use them beyond the period. Or prepare smaller batches if you don’t drink often.
Grinding is breaking down the roasted coffee beans into coarse, medium-coarse, or fine ground particles. It can be either done with the help of a manual grinder, electric grinder, or a super-automatic espresso machine.
Manual grinders will not have enough settings for a finer grind. So, make sure to choose a manual grinder with the most refined settings if you enjoy espresso shots every morning. Espresso demands the finest of the ground.
If you prefer multiple brewing methods, buy a grinder that supports every brewing grind size from coarse to the finest grind.
Manual grinders are affordable and classy but they demand manual actions. If you don’t have the time for it, buy an electric grinder.
Electric grinders will offer many grind size settings when bought from a good manufacturer. So, choose wisely.
Every different brewing method will demand a different grind.
Benefits of Fermented coffee
Surprisingly enough, fermented coffee has many health benefits as well. Increasing the quality of the coffee, you are sipping protects it longer and makes it taste better.
There’s no doubt a regular coffee also has its charisma, but when it’s fermented, those characteristics heighten, giving you a rich beverage.
Please note: If you are fermenting your coffee, it might take a couple of trials and errors to attain the actual flavors and aroma of a fermented coffee.
Fermenting your coffee has a learning curve; a small disturbance ruins your batch. Thus, you must make sure to have patience while trying to experiment with it. With errors, you will eventually learn how to perfect your coffee.
Easier on your stomach
As said, fermentation means breaking down giant molecules into smaller substances. When you ferment your coffee, you digest many giant molecules that are hard to digest for your stomach.
Regular coffee has more extensive components and carbs, making it hard for people to drink who have weak digestion or are dealing with stomach issues.
The same is not the case with fermented coffee; it’s actually very mild on your stomach. Anyone with an upset stomach and weak digestion symptoms can consume fermented coffee with peace of mind.
Second, when you drink fermented coffee, you consume most of the healthy bacteria and yeasts. These microorganisms improve gut health and help yourdigestion. These microorganisms also help in easier food absorption and assimilation.
These microorganisms are rich in prebiotics that increase the number of healthy bacteria in your gut for even faster metabolism and digestion.
Doesn’t cause IBS
IBS stands for Irritable bowel syndrome. It’s a mild disease but may cause extreme distress. The discomfort might include stomach ache, diarrhea, constipation, cramps, excessive contraction of the large intestine during digestion.
Although the reasons for IBS are unclear, certain foods, including coffee, may cause IBS. Fortunately, fermented coffee doesn’t cause IBS, and you can drink coffee without fear of a sore stomach, cramps, constipation, or diarrhea.
Fermented coffee lasts longer.
Healthy bacteria and yeast in your coffee fights off pathogens and unhealthy microscopic formation that can affect your coffee’s health and age.
Deters fungus growth
It also deters fungus growth.
As widely stated, fermented coffee will have an enhanced taste compared to regular coffee. Truth be told, regular coffee is often bitter-sweet with low notes of sweetness, mild fruity-taste, mute chocolate, and a cup full of sourness.
So is not the case with fermented or cultured coffee. When you ferment coffee, you are allowing those fruity tones to surface up. In breaking down the complex starch and sugar, the byproducts are sweet alcohol, ethanol, and many acids.
These acids and ethanol give a sweet, malty taste to your beverage. Not only this, but you are breaking through many complex but hidden undertones. When broken, these undernotes do not stay hidden and create an intense flavor.
The acidic body is optimal with smooth and textured composition. Fermented coffee releases undertones including caramel, chocolate, dark chocolate, fruits, blue fruits like blueberry and red berry, or citrus fruits with tangy, juicy acidity.
Please note: Every different method will yield a different flavor profile. Often, dry fermentation will yield chocolatey notes along with blue fruits.
On the other hand, wet fermentation will yield orange/yellow fruits with a hearted-acidity that won’t burn your stomach. Usually, fermented coffee will have a pH of 5 or 6. A third fermentation will further enhance the taste and these notes.
Not only the flavor but fermented coffee also releases many different aromas while breaking down molecules. When fermentation breaks, the substances, taste, and smell intensify and release themselves out in the cup.
While breaking down many such components, fermented coffee breaks down caffeine into smaller molecules, thus decaf-ing the beverage and the coffee beans.
Once the coffee is decaf, it has close to no bitter taste and no burnt or dark solid aromas. Once the caffeine is out of the content, the coffee smells fruity and chocolatey without any hints of bitterness.
It doesn’t turn your teeth yellow.
Similarly, tannins are primary and secondary antioxidants such as polyphenol. Unfortunately, they have more side effects than they have benefits. Above all, tannins have a very sour and bitter taste.
Fortunately, once you start fermenting, the coffee/teas start to lose tannins. Once they are removed, half of the bitterness is already gone. Tannins are one of the major components responsible for the bitter taste of coffee and tea.
The leftover tannins give away the dark-chocolate taste preferred by many individuals.
They will turn your teeth yellow with everyday consumption. This is a result for every heavy consumer/mild consumer of tea/coffee or both.
Both tea and coffee have a considerable amount of tannins to go with, which reduces down at the introduction of water. If you want to get rid of the bitterness, soak and ferment your coffee/tea.
How do tannins cause yellowness in your teeth?
They facilitate the color compound to stick to your teeth. When your teeth are exposed, these color compounds stick longer, they tend to leave a yellow hue on your teeth.
Every day of regular coffee will result in yellow teeth; just one cup of regular coffee a day is enough to get yellow teeth. When you ferment the coffee in water, you allow the tannins to float out from the coffee beans into the water.
So, fermented coffee has a significantly less amount of tannins and doesn’t turn your teeth yellow
What is the flavor profile?
The flavor profile of fermented coffee will always differ depending on the type of coffee beans, the origin of these coffee beans, the soil they are grown in, the coffee process they go through (wet, dry, honey, wet-hulled processing), etc.
Arabica coffee beans of any origin will have a high sweetened taste, not sugary, but sweet fruity flavors.
The fruity undernotes can depend on the coffee beans and where they are grown. Every different origin will have a different fruity taste with enhanced and intensified flavors after fermentation.
A universal flavor profile can depend on the various coffee processing methods.
Dry process: Dry processed coffee is the most natural amongst the other methods. The cherries are dried until they can crunch away the parchment and leave behind the coffee beans.
Dry processed coffee beans are sweetest because they are left with the cherry for a long time to soak in many flavors and notes from it.
Coffee cherries have a taste similar to red fruits and can be mild, sweet, and juicy. All these flavors are absorbed by the coffee beans while being dried.
Dry processed flavor profile: So, when you ferment dry beans, you will have a sweet flavor profile of red/ blue fruits, flavors of dried fruits like raisins, and caramel. You might also notice evident hints of black fruits.
Wet processed: Wet processed beans involve soaking the beans in water, fermenting away the mucilage and drying the parchment.
Wet processed, fermented coffee flavor profile: Since these were wet fermented, these coffee beans will have an influenced taste of wine and beer, a slight pinch of alcohol, and sweet acidity.
These coffee beans will have yellow/orange fruit intense notes, evitable in every sip. The edge is moderately sour and moderately tangy like the lemon or the plum.
Overall, fermentation intensifies, enhances, overproduces, and brings out those hidden flavors of coffee beans. They don’t change the taste of coffee; they amplify the taste of coffee for you to enjoy it without bitterness.
How does fermentation happen naturally?
Fermentation is a biological process involving a chemical reaction when water and sugar are present in fruit, vegetables, or edible resources. Please note: fermentation doesn’t equate to rotting.
It leads to the nutritional breakdown of molecules in the presence of healthy bacteria and yeasts.
Rotting, on the other hand, happens when harmful yeast or bacteria starts to conjure your food. In fact, fermentation preserves the food from rotting by killing off off harmful bacteria.
Coffee has sugar and water present inside of it in abundance. Naturally, it attracts healthy yeast and bacteria and starts the procedure of breaking it down. When cherries ripen from green to juicy red cherries, they are ready for natural fermentation.
Coffee farmers who prefer dry processing witness natural fermenting. Dry processing or natural fermentation must be equally monitored because temperature and humidity can affect it adversely.
A moderate temperature of 32-35 degrees accelerates and balances fermentation, but a slight increase can fasten the process leaving many unattended areas.
Higher temperature can result in low ethanol yield and yeast sensitivity.
A slight fluctuation is normal, but a constant high temperature can ruin the natural process.
Similarly, mild humidity doesn’t affect it, but higher humidity for extended periods can mold your coffee beans. So, make sure you monitor these aspects when dry fermenting or allowing it to happen naturally.
How do you ferment coffee at home?
Most people prefer fermenting coffee as a beverage after brewing rather than fermenting beans, but it will yield even better results if you choose to work with the beans.
People often avoid fermenting coffee beans because it’s a rather lengthy and challenging process. Also, roasting coffee beans is more complex than one might wonder.
Needless to say, traditional roasting will give you a more personalized and detailed roast, but it takes patience to learn it.
To ferment coffee beans:
- Buy beans that are fermented once to remove the mucilage, are parchment less, and dried well. These beans usually have a light green color.
- Soak these coffee beans in water and have 1-2 inches of water covering it.
- Add sugar to it
- Add the SCOBY, a homemade yeast culture, or one-day-old yeast water.
- Allow it to rest in optimal condition for 1-2 days. Make sure to place the beans in moderate temperature and humidity.
- After the given period, wash these coffee beans to get rid of the culture on the surface.
- Dry them until stiff. Break a bean to check if it’s ready for roasting.
- Roast the beans on low flame and occasionally stir them on a traditional stove. Roast until the color is pigmented brown with a light shine or if you prefer a dark roast, allow it to roast until dark brown with a heavy, shiny oil layer.
- Let the roasted beans de-gas for 2-3 days or more, and then grind them for brewing.
To ferment the coffee beverage:
- Fill two jars with 1-liter coffee.
- Add sugar or any other sweetener to provide sugar for fermentation.
- You can either add water kefir as the culture (yeast/bacteria culture) or use Kombucha coffee as a starter culture. Both can be readily available on a kombucha store, or kefir can be produced at home as well (discussed later in the article)
- Close the jar with a thick cheesecloth/cotton cloth. Do not screw the lids; fabric will be enough.
- Allow the coffee to rest for 2-3 days and monitor it closely.
- It will have many trials and errors because the fermentation period can largely depend on the environment it’s kept in. You can try to match your fermented coffee’s taste with Kombucha’s original flavor as a taster.
How does caffeine affect yeast fermentation?
Caffeine doesn’t have many influencing effects on yeast fermentation. Many chemical/biological studies suggest that caffeine promotes the growth of baker’s yeast, but that doesn’t apply to this.
On the other hand, caffeine is broken down into a simpler substance when coffee is fermented. Thus, when you drink a fermented beverage, there’s a lot less caffeine than regular coffee.
However, many ready-made fermented drinks have started to add additional caffeine in their drinks to provide caffeine drinkers the boost.
Usually, a fermented coffee like the Kombucha will have 15mg of caffeine, but with more and more requests, a kombucha (a popular fermented drink) now comes with enough caffeine content. A rough calculation shows that Kombucha now has 130mg of caffeine per bottle.
They increased the content with the help of natural tea leaves that were high in caffeine content.
If you wish to brew a caffeinated fermented beverage, increase natural caffeine content. You can use a blend of robusta and arabica beans
What is cultured coffee?
By definition, cultured coffee means coffee that’s been put through a bacteria culture and transformed into a product of that specific culture. In this context, culture means a starter medium of microorganisms to facilitate fermentation in living things.
Cultured coffee is the second name for fermented coffee. This coffee is put through a culture of bacteria and yeasts or SCOBY to ferment and breakdown more giant molecules into smaller ones.
Second, cultured coffee is a product and a company’s name that produces fermented coffee.
Unlike Kombucha, which uses tea leaves as the main product, Cultured Coffee uses coffee beans and extensive machinery fermentation to ferment the beans. Kombucha is a drink served at establishments, but cultured coffee produces and sells fermented beans!
So, if you want to drink fermented coffee made of coffee beans and not tea leaves but don’t have the time or patience to do it yourself, cultured coffee will be your go-to-website store.
Can cold brew coffee ferment?
Naturally, no! Artificially, possibly!
Before explaining both of these statements, you must first know what a cold brew is. Cold-brew refers to the process of how it’s brewed rather than the temperature of the beverage.
The process of cold brew is simple but may confuse people:
- Grind the number of coffee beans you’d like to brew. Cold-brew can be brewed in bigger batches. So, feel free to grind enough.
- Once ground well, pour or scoop this ground in a big jar/french press.
- Add water to the jar with whatever coffee ratio you prefer. You can use a similar percentage of the french press (1:12-1:14- 1gram of coffee ground to 12-14 grams of water). You can increase or decrease the volume of water depending on your preference for a darker/lighter taste.
- Now, the centered magic of cold brew begins. Stir coffee and water together and allow them to rest for 12-16 hours at room temperature or in the refrigerator.
- Once the hours are finished, strain the coffee ground and pour the beverage over ice in a glass for iced cold brew.
Fermentation requires sugar and water to activate the process. Naturally, cold brew has a tremendous amount of water, but coffee doesn’t contain sugar. So, even if your cold brew has been sitting for hours, it won’t ferment. It will simply oxidize and age with time.
Artificially, you can add sugar and SCOBY to the cold brew once the 16-hour cycle is finished and wait for another 24-48 hours to drink fermented cold brew. This is based on your personal experience and experimentation.
Can you make alcohol out of coffee?
Fermentation does release a small amount of alcohol, but it’s close to negligible. You might see 1% of alcohol in fermented coffee or even less. Some companies ferment coffee beans without the slightest hint of alcohol and claim to have zero percent alcohol.
But as you see, the whole process isn’t in our hands except for the environmental condition and outside maintenance. Thus, we might never know how much alcohol it produces; it can be 1% or less depending on the hours invested while managing the coffee and yeast activity.
You cannot make alcohol out of coffee beans but you might get tipsy after drinking more than 5-6 kombucha bottles of fermented liquor.
Scientists are now studying a way to create alcohol out of used coffee grounds.
- These used grounds are collected from a big cafe, places with giant coffee ground dispensers.
- Used coffee grounds are then heated with water at 162 degrees celsius.
- The water is then separated from the coffee grounds.
- Next, they add sugar to the coffee water and then the yeast or SCOBY.
- Once the starter culture is prepared, it’s left to ferment.
- After fermentation, the fluid is concentrated to increase alcohol content.
The experiment was quite successful and discovered almost 40-45% alcohol in the said beverage with similar alcohol effects.
Wet fermentation process
The procedure of processing coffee through water and later drying it is considered wet-processing of the coffee beans. It’s the second most popular way of processing beans next to dry processing.
In wet processing,
- The ripe red coffee cherries are plucked and hand-picked.
- Next, these cherries are de-pulped in big machinery.
- After de-pulping, the cherry is left with many juicy, protective layers, especially mucilage and parchment.
- Coffee farmers perform a wet fermentation process to remove the mucilage layer of the coffee beans and harden the parchment.
- To wet ferment, pour the de-pulped coffee beans in water and allow water to inch above the coffee beans.
- This fermentation can take 24-48 hours to remove the mucilage and harden the parchment. You can remove the beans from the water once you feel the beans getting harder.
- Wash the beans and dry them well. Drying is essential to avoid molding. So, dry on raised beds under the sun until it shows the dried parchment.
- Parchment can be removed manually or through pieces of machinery (done for Sumatran beans).
- The beans are then packed and shipped.
Benefits of wet fermentation process:
- Wet fermentation is the easiest and the most high-yield process.
- It doesn’t lead to many errors, defaulted beans, or low-quality beans.
- This process gives away a smooth body, slightly acidic, and tangy, winey flavors to the coffee beans.
- It gives consistency to the beans and throughout the roasting stage.
- Most of the wet fermentation process is in your hands, and you can manage it more personally.
- It washes away the tannins (the bitter agent in coffee beans)
Cons of wet fermentation.
- It cannot be done in humid areas, and places frequented with a lot of rain because wet processing demands sun for several weeks to properly dry out the coffee beans.
- It’s not as fruity as dry-processed beans.
- A lot is washed away while wet processing the coffee beans.
Dry fermentation process
Unlike wet processing, dry processing allows natural fermentation and direct heat to dry out the pulp and other layers. It’s the most practiced method while processing coffee because it requires minimum expenditure and machines.
To dry process coffee:
- Farmers pluck red cherries and hand-pick the best ones.
- These cherries are then spread on raised beds and allowed to dry out in the sun.
- Once the cherries dry out, they are crushed to take out the beans.
Pros of dry fermentation process:
- The dry process allows the coffee beans to soak the fruity cherries content through the pores. This absorption gives coffee beans the sweetest fruity taste.
- It doesn’t ask for much expenditure and is the cheapest of all.
Cons of dry fermentation process:
- Coffee beans that are dried are at a greater risk of damage because the sun can be very unforgiving.
- It would help if you had optimal temperature to dry the beans. This temperature must be maintained at around 32-35 degrees. Since you cannot maintain the temperature the sun radiates, a lot can be damaged if the temperature exceeds the limit.
Types of fermentation
After the natural fermentation and farmer-induced second fermentation, the third fermentation that companies have started can be done in three simple ways.
Please note: All these three methods are different. Some are done at coffee beans level, the others on beverage levels.
You must have heard that kopi luwak is the most expensive coffee bean out there. Its high price is due to the fermentation process. Kopi luwak coffee beans are semi-digested feces of civet, a small animal hybrid of a raccoon and a cat.
Civets are known to pick only high-quality coffee beans, eat those beans, half digest them and excrete them—the half-digestion results in a healthy fermentation of coffee beans. Civets provide an excellent medium for the fermentation to take place properly.
Once the civets excrete out half-digested coffee beans, they are appropriately washed and then roasted. Kopi luwak is expensive because:
- Low-yield coffee beans per day because there’s a limit to how much civets can eat and defecate.
- The process results in great coffee beans altogether and naturally fermented.
Unfortunately, kopi luwak has been known for animal abuse where civets are left in cages, force-fed coffee beans to yield a more significant amount of coffee beans. It’s also stated 80% of Kopi Luwak are fake to increase sales and sell regular beans for higher prices.
If you want to drink fermented coffee, please try other fermented coffee beans like Kombucha or cultured coffee.
Kombucha cannot be considered fermented coffee because it’s made of tea. Brewing Kombucha is quite simple. All you need is tea (black or green), yeast, and sugar.
- Once you brew the tea, add sugar since fermentation needs both sugar and water.
- Once the sugar is completely dissolved, add yeast or bacteria as a starter culture.
- Kombuchas are then put in a container that is later covered by a cheesecloth.
- Kombuchas are left to sit for 2-3 days or sometimes even a week until SCOBY starts building up in the jar. The SCOBY builds up when fermentation is happening. SCOBY can be used for the next batch or sold to prepare homemade Kombucha.
- Kombucha usually has low caffeine.
Kefir coffee is also fermented at the beverage stage. After brewing coffee, add water kefir or milk kefir to the beverage and allow it to rest for 1-2 days.
You can either use milk kefir for your beverage fermentation or water kefir.
- Milk kefir: Milk kefir uses kefir grains, lactose milk rich in sugar to ferment. When combined and allowed to rest for 1-2 days, all these become fermented milk kefir.
- Water kefir: Unlike milk kefir, water kefir doesn’t use milk for sugar. Instead, you can make a starter culture of water, kefir grains, and sugar and allow them to rest for 1-2 days for it to ferment properly.
Both the kefir will take additional 1-2 days to ferment the beverage. With milk kefir, you will be rendered with extra sweet dairy-added coffee.
Not only is fermented coffee tasty, but it also has many health benefits to offer. For a change, switch to a naturally sweet and flavored coffee rich in healthy bacteria, yeasts, prebiotics.
Also, fermented or cultured coffee is excellent for people who are willing to cut down their caffeine intake. On the same note, it is also suitable for gut health, irritable stomach, and weak digestion.
Brew and ferment your coffee beans today and enjoy the healthy change!