Microorganisms, fermentation & the sensory profile of coffee
As the coffee industry develops and grows, producers and researchers continue to innovate and push boundaries in regards to processing and fermentation. The end goal is to deliver unbelievable flavours and improve cup quality.
Whenever fermentation is involved, producers and scientists experiment with various microorganisms, and examine how their unique relationship with the process can affect a coffee’s sensory profile and cup score.
FERMENTATION, MICROORGANISMS, AND CONTROLLED FERMENTATION
Coffee fermentation is a naturally occurring process that starts to occur as soon as a coffee cherry is picked. It occurs as the water, sugar, and starches within the cherry begin to naturally break down into acids and alcohols.
Fermentation typically occurs in one of two main ways: aerobic (an oxygen-rich environment) or anaerobic (an environment with no oxygen). Both fermentation styles can be controlled in different ways.
Whenever fermentation occurs, microorganisms are responsible for converting these sugars and starches into acids and alcohols. There are thousands of microorganisms that have been identified in fermentation, but some of the most common include yeasts (such as saccharomyces cerevisiae), bacteria (such as lactobacillus), and fungi.
Each individual microorganism affects fermentation (and therefore coffee flavour) in an acutely different way. While we understand that some (in particular saccharomyces cerevisiae and lactobacillus) affect the smell, colour, and pH of a coffee, the effects that other microorganisms have on fermentation are still being studied.
More recently, controlled fermentation has been adopted across the coffee sector to offer increased security for producers who experiment with coffee processing. By monitoring and controlling variables such as temperature and time, producers can more effectively manage the flavours of their coffee, and subsequently manipulate its sensory profile.
