Fermentation in coffee processing is becoming more and more popular. Is it a major trend or is it here to stay?
First we need to clarify what actually is fermentation. Then we can try to guess why it is becoming more popular and how it can affect the cup profile. In the end we can have a brief and personal view about extreme fermentation techniques.
Fermentation put simply is a chemical reaction that happens when yeast, bacteria and fungi causes a substance to break down into sugars. This results in increased temperature. In the beginning fermentation was introduced as the cheapest way to remove mucilage. The higher the temperature and the thicker the mucilage the faster the fermentation occurs.
The term “fermentation” is widely used nowadays to describe any metabolic process carried out by microorganisms on food – think about yogurt, wine, beer, pickles just no tame a few.
Fermentation process could be divided into two main ways: aerobic or anaerobic. The key role here is played by the presence or not of oxygen. The anaerobic fermentation is carried out into tanks filled up with water so that microorganisms can start working on coffee cherries soaked into water. These procedure is easier to monitor and produces a more consistent result.
Aerobic and anaerobic fermentation are the two main categories but in recent years farmers and coffee experts came up with new and innovative techniques, looking at what is used in wine-making and how to dear with carbon dioxide, yeast and other starters like acids and bacteria.
Experimenting is the only way to learn more about coffee processing and studying the outcomes allows us to better understand how coffee quality could be impacted by these reactions.
Coffee fermentation should be understood, monitored and results must be recorded as to make the process the more consistent it could be. When fermentation is carried out in a controlled way it could be for sure enhance the positive attributes of the cherry: acidity, sweetness and give a clear cup. When fermentation is rather wild and uncontrolled we will have a very disappointing outcome: moldy, flat and chemical flavors in our final cup.
There are three main factors that producers should monitor very carefully while fermentation is undergoing: time, temperature and water quality. Because if one of the above factor is unbalanced – high temperature or for instance too long fermentation time – results could lead to a very bad outcome. Brix reading is essential as it measures the sucrose in the juice of coffee cherries [Brix range for coffee is 15°-25°, 1°=1g of sucrose/100g solution].
We don’t want to go too deep into this post about chemical reactions and other technical indicators as what we wish to point out is the outcome of this process and why fermentation is so important in the coffee sector: as to enhance coffee quality.
We could now ask a provocative question: what is really coffee quality? When it comes to quality it is not so easy to define it as personal perspective remains predominant. We could have standards about the process and the procedures that must be followed, the taints and defects we should not find in our cup but saying that one coffee is better than the other, or that it is of a better quality remains a personal issue.
Do we really appreciate extreme fermentation techniques that lead to a final coffee that smells and tastes of yeast, vinegar, very acidic with low sweetness, full body… Manipulating the coffee profile through fermentation is a unique chance we have to see how the final outcome will be but at the same time it could be very risky as the final consumer might not be ready to understand such cup profiles.
Not only producers have to deal with yeasts, microorganism and additional factors but also the climate conditions have a main impact on the outcome: humidity and temperature, pH and water availability and fruit maturation.
As to conclude this brief overview about fermentation we can say that this gives the producers the opportunity to play with their product and differentiate themselves, they will have a wider variety of products to offer to the final consumers and be more competitive on the market. Until now coffee profile has been “manipulated” by artisan roaster using different roasting profiles, now having coffees already differentiated at origin will open new and interesting scenarios for coffee lovers.
Coffee lovers and roaster by their side will have the chance to “play” with unique tropical flavors and new and unusual cup profiles. This will determine what is quality and what’s not, far from cup scoring numbers.