COFFEE WASHING PROCESS

Anaerobic 200H

In comparison to aerobic fermentation, anaerobic fermentation produces distinct acids such as lactic acid which can boost the coffee’s cup-profile and create remarkable flavours.

Firstly, ripe cherries are harvested and pulped (where the skin of the cherries are removed). The pulped cherries where the parchment with mucilage are still intact will be placed into an airtight stainless steel tank that has a valve which is used for degassing. In this sealed tank, the temperature is controlled and fermentation will take place for hours or even up to days, depending on the environmental conditions (in this case, 200H).

During fermentation, CO2 is released and pressure starts to build up. The pre-existing pressure and whatever oxygen that was in the tank will be released through the valve attached to the tank. The resultant pressure from the CO2 forces the juices and sugars from the fruits’ flesh into the parchment, altering the flavours of the bean greatly. This is a critical point in the process: the fermentation has to be stopped once all sugars in the mucilage have been consumed.

Thereafter, the beans are gently washed and drying has to be done quickly in order to stop further fermentation as the flavours would be affected. The beans will be dried through brick patios, raised beds or through a mechanical dryer. To ensure even and consistent drying, the beans will be turned regularly. What is left on the coffee beans then, will be a thin layer of skin known as the parchment skin, and this skin will be removed through the last step in the process which is known as hulling.

Although the cup-quality of anaerobic-processed coffees are impressive, this process is difficult and it requires good skill and expertise. Notable cupping notes from this processing method include: fragrant and fruity aroma, sweet and expressive flavour notes like honey, wine, nuts, citrus.



Anaerobic 200H
Pick Ripe Cherries
In the picking stage, the level of ripeness and elevation of fresh fruits (cherries) are critical. Red and purple-red cherries produce the best flavours, while under-ripe (green) and over-ripe cherries produce astringent tastes which deteriorate the overall cup-quality. Often, red-cherries grown at higher altitudes are highly demanded as it produces better flavours due to better maturity and higher sugar content.
Submerge in Water
Submerging is a process of removing impurities from the harvest. Through the fluidity and gravity of water, the immature fruits, floaters, withered beans, sticks and leaves are removed. When the fresh cherries are submerged in water, the pulp which carries microorganisms will hasten the fermentation process.
Depulp
After Cherries are harvested, they have to be depulped within 24 hours or else the cherries may produce an overly fruity or rotten flavour that can ruin the coffee’s cup-quality. Depulping is the process of separating the coffee seeds from the outer layer of flesh from the fruit and it usually happens at the farm or a centralized depulping station.
Ferment
During fermentation, microorganisms in mucilage will react with sugar to degrade, leading to fermentation. This is an essential stage of coffee processing as this is when microorganisms interact with enzymes and amazing flavours are developed. The coffee fragrance changes from fresh fruits to berry-like, transforming into tropical fruits and rich red wine - the ideal state of natural fermentation.
Dry
Drying is a phase where the quality of the green bean and developed coffee flavours are preserved. Typically, drying takes about 23 days and during this period the water content in the coffee beans are reduced to the appropriate range at around 10-12%. Usually, drying is done with a suitable temperature through using convective hot air