What is Lactic Fermentation?
Lactic fermentation is a process of controlled microbial breakdown of coffee cherries during which lactic acid bacteria (LAB) consume the sugars in the coffee fruit and produce lactic acid. This process is one of several types of fermentation used in coffee processing to enhance the flavor and quality of the final product. During lactic fermentation, the LAB bacteria not only produce lactic acid but also produce enzymes that break down complex proteins into free amino acids. This contributes to the development of some of the attributes that make up the coffee's sensory profile such as the “umami” flavor.
To initiate lactic fermentation, the coffee cherries are typically picked and then carefully sorted to remove any unripe or damaged fruits. The cherries are then placed in water-filled tanks or barrels where they are allowed to ferment for a period of time ranging from 12 to 48 hours. During this time, the LAB bacteria multiply and begin to consume the sugars in the cherries, converting them into lactic acid. After the desired level of fermentation is reached, the cherries are typically washed and dried, either in the sun or using mechanical dryers.
Lactic fermentation is one of several fermentation methods used in coffee processing, each of which can produce unique flavor profiles. By controlling the fermentation process, coffee producers can manipulate the flavor of the coffee beans, creating distinctive and highly sought-after tastes that appeal to coffee connoisseurs around the world.