Have you ever thought what makes your coffee taste good? A study conducted on coffee revealed some surprising facts. It showed that lactic acid bacteria help in the longer fermentation of coffee beans which results in better taste. The study was conducted at Vrije Universiteit Brussel, in Belgium and Professor Luc De Vuyst was the lead investigator in this study. He said, “A cup of coffee is the final product of a complex chain of operations: farming, post-harvest processing, roasting and brewing.”
He also mentioned that the bacteria play a significant role in making coffee taste great by fighting off other undesirable micro-organisms. Including this, there are several variants of post-harvest processing, such as wet processing and dry processing. Wet processing is commonly used for Arabica and speciality coffees. It includes fermentation in one of the processing steps.
The team found that during extended fermentation, leuconostocs — a genus of lactic acid bacteria used in the fermentation of cabbage to sauerkraut and in sourdough starters — declined in favour of lactobacilli.
De Vuyst said, “It is challenging to draw a causal link between the microbiota and the volatile compounds in the beans – those compounds that contribute to the coffee’s smell – since many of these compounds can be of microbial, endogenous bean metabolism, or chemical origin.”
He also observed that lactic acid bacteria showed an impact on coffee beans. He stated, “It may have had a protective effect toward coffee quality during fermentation because of their acidification of the fermenting mass, providing a stable microbial environment and hence preventing the growth of undesirable micro-organisms that often lead to off-flavours.”
Other than lactic acid bacteria, other micro-organisms also play an important role in wet fermentation includes enterobacteria, yeasts, acetic acid bacteria, bacilli and filamentous fungi. But it is still not known how most bacteria influence this process.