Today at The Coffee Shop, we'll talk about coffee fermentation processes and how they directly impact its flavor. The fermentation process is critical to shaping coffee 's flavor because, like wine, it produces the cup's acidity and fruity notes through the breakdown of sugars by yeast and bacteria. Because coffee cherries begin fermenting shortly after picking, the way the farmer or local cooperative handles this process has a direct impact on the coffee's final flavor. Processing methods vary depending on geography, climate, logistics, and tradition.
Let's start by explaining the purpose of fermentation . A coffee bean begins its journey as a coffee cherry, with the beans in the center of the cherry. When the berry has been picked, the pulp is removed by machine, leaving only the bean. However, there is still a part surrounding the bean: a pectin-based mucus layer called mucilage. The ultimate purpose of fermentation is to remove this layer and facilitate the chemical transformations within the coffee beans.
There are three ways we can ferment coffee beans. We'll explain the basic methods, but we understand that there are much more in-depth and experimental methods used by coffee growers.
The washed method
During the washing method, the harvested berries are first soaked to separate the ripe berries from the unripe ones. Ripe berries will sink to the bottom, while unripe berries typically float due to their lower density.
The unripe beans are immediately removed. A pulper then removes the pulp from the coffee beans. Finally, the freshly hulled beans are fed through water channels that will lead them to fermentation tanks. This is where the fermentation process takes place. The beans, still encased in a shell called "parchment," will ferment, loosening the pulp and any remaining mucus. This process takes between one and two days.
After washing the residues that have been fermented by the process, only the parchment husk remains around the beans. Once the beans have dried, this husk can be removed with a hulling machine. After hulling, they are sorted by size using sieves and packaged.
The "Honey" method
During the Honey process, the coffee cherry pulp is removed. However, a small percentage of this pulp remains during drying; we call this honey. The honey ultimately provides the coffee bean's unique flavor. The honey ferments on the bean for a period of 18 to 25 days.
The advantage of this method compared to the dry method is the fact that this method involves less deterioration because the pulp has been largely removed.
The dry method
The dry method is very labor-intensive due to all the work done on the drying beds. Furthermore, the dry method requires very selective harvesting, as unripe berries cannot be sorted by machine. The first difference with respect to other methods is that, with the dry method, the coffee cherries do not first go through the pulper.
After this, we thoroughly dry the coffee cherries. This ensures greater flavor transfer between the pulp and the bean. It's also easier to remove the cherries from the bean after drying. This method requires little equipment, but it is highly dependent on the circumstances. For example, humidity must be just right, so any rain can disrupt the process. This also makes this method impossible to implement in some areas.
How does fermentation affect coffee quality?
There is a wide range of different flavors that can be produced through fermentation. Fermentation can refine the sweetness, body, and acidity of coffee, and even add a fruity note.
However, keep in mind that when coffee is poorly fermented, it can result in a moldy taste, which ruins the flavors. That's why it's crucial to monitor the process and properly understand how fermentation works.
Time is a crucial factor, and under- or over-fermented coffee can cause a loss of quality, such as sweetness, acidity, and body. If fermentation is done correctly, it can bring out the coffee's best characteristics and flavor. This is how you let exotic coffee come into play and open up a new world of flavors.
Humidity, for example, affects the coffee fermentation process and dictates the best method. Wet processing in a can will produce different coffee bodies and results. This is to ensure consistency in bean quality, where factors such as temperature, moisture content, and even airflow all contribute to making high-quality coffee.
We hope you found the coffee fermentation process interesting. Now we know how meticulous and important the fermentation process is for the final result in our cup to be so sublime and of such high quality. But we also know why sometimes a cup of coffee made blind can be disappointing. If you don't want that to happen to you, you can visit our store, browse, and choose for yourself.