What is coffee fermentation?
Coffee fermentation is not necessarily a new trend- various processing methods for a variety of beverages have incorporated fermentation throughout human history. Technically, all coffees are fermented. The explosion in popularity amongst coffee producers, however, is new. Farms are, more and more each season, employing a vast array of yeasts, fruits, and fungi.
Fermentation is produced by microorganisms that activate the process spontaneously, where different chemical reactions take place. Similarly, fermentation can be defined as those methods of preservation in which microorganisms act by generating anaerobic biochemical reactions, that is to say, that air and oxygen are subtracted. Basically, it is the chemical breakdown of a substance caused by the enzymatic action of yeasts, bacteria and microorganisms.
In a simpler way, fermentation is the natural transformation that occurs when sugars and water are combined. These two elements are not exempt in coffee cherries, which allow for different methods of coffee fermentation.
Fermentation actually improves the coffee flavors, and after the coffee harvest, fermentation is a fundamental and essential part of the coffee process.
We at Viewfinder have offered several different fermentation styles in our line-up, just to name a few we have currently:
Koji Gear 5- Finca Gascon
Koji co-fermented Guatemala
This fermentation process occurs through spores of the filamentous fungus A. Oryzae.
This new method can potentially generate new opportunities for coffee farms since koji has a unique property to take advantage of the remaining 30% of the sugars. Koji also can be grown on practically any starch, which is amazing because it can be grown on previously unused coffee bean starches such as skin, mucilage, and pulp.In this process, the coffee cherries are taken to the first stage of fermentation lasting 3 days; subsequently, the A. Oryzae spores are applied to the surface of the cherries themselves and left for another 60 hours of fermentation. At this point, the drying process is continued to achieve a final moisture content, followed by hulling and finally packaging and transport to the roasters.
Depending on the roasting profile of the coffee, the flavor varies widely from tropical fruits such as pineapple and mango to chocolate and gingerbread.
The War on Yeast- Finca Gascon
Yeast inoculated co-fermented Guatemala
This process occurs when reactivated yeast is combined with washed coffee cherries in a controlled environment, often anaerobic. To be clear, yeast as a microorganism is everywhere. The main source of yeast in any given coffee fermentation is the skin of the coffee cherries. Even human skin is a source for yeast. Coffees in Rwanda for example are often washed by workers entering the tanks and using their feet. This is by and large the most common method we are seeing nowadays. Inoculated yeast, however, is a yeast that is not native to the coffee itself, and not from any fruits or bacteria found in the environment around the coffee (wild fermentation). This yeast is purchased or cultivated for the express purpose of fermentation, similar to kombucha. Depending on the coffee's roast profile, these can be very aromatic coffees, with a ton of berry acidity and more flamboyant personalities.