Colombia is the pioneer of this new coffee processing method. These once experimental methods have element of wanting to push the boundaries of flavor and push the boundaries of what coffee can truly become. After several years of development by professional producers in origin countries, especially Colombia, some methods have gained their position in the specialty coffee world. Other than the mature Carbonic Maceration from established estate, who have developed their own signature methods. The processes are getting more and more sophicated, using many scientifc measurement like pH value, Brix, temperature, etc. in order to produce consistent results.
Coffee Fermentation is getting more and more mature. Fermentation process is all about experimenting soaking periods, wash frequencies, drying environments, and other variables. This chart shows a board sense of classification by grouping them into anaerobic and aerobic.
Anaerobic fermentation – coffee cherries are locked into an airtight fermentation tank after being harvested, to stop any oxygen from getting in.
Carbonic maceration – cherries are locked in the airtight tank after harvest, just as with anaerobic fermentation, but are then flushed with CO2.
Lactic process – allows for the growth of lactic acid bacteria under anaerobic conditions with constant measurement of oxygen level, sugar content, and pH.
Dry fermentation – letting the coffees rest in climate controlled fermentation tanks post de-muchilaging, rests warm and dry while fermentation kickstarts
Acetic process – cherries are collected into plastic tanks with water. The water is then oxygenated, encouraging the development of aerobic bacteria like acetobacter for fermentation.
Among these process, anaerobic has evoloved to before a rather standard fermentation mehtods that already spread out the world. We can now find anaerobic processed coffee in more central american origins, as well as Ethiopia, Sumatra, etc.
The latest trend is mixed fermentation, some time referred as double fermentation. For producers willing to revive more details, these mixed process usually involve both anerobic and aerobic process.
The fermented coffee is very popular in Asian markets. We should be lucky to live in Hong Kong that many roaster and traders are actively introducing these state-of-the-art coffee to challenge our taste.