High quality premium chocolate has a particularly noble taste. However, this only arises from cocoa beans of certain origin – at least so far. Now researchers have identified the microorganisms that naturally ferment the cocoa beans and provide the noble taste profile. With this knowledge, the spontaneous fermentation process can now be reproduced in the laboratory and in production systems under controlled conditions-regardless of which farm the cocoa beans come from. This recipe could help improve the industrial production of noble chocolate.
Many foods are manufactured or refined using microorganisms. The microbes use their enzymes to ferment the raw ingredients. For example, in the production of wine, beer, cheese or bread dough, microbes are specifically added to achieve the desired taste experience. Microorganisms are also involved in the production of chocolate, which ensure the unique chocolate taste. However, these microbes ferment the beans of the cocoa lances (Theobroma Cacao L.) spontaneously without being deliberately added. How a chocolate tastes in the end therefore depends primarily on the location of the cocoa farms and the microbes that occur naturally.
“The fermentation typically takes place directly on the cocoa farms, where the harvested beans are stacked in wooden boxes, baskets or piles. Bacteria and mushrooms from the surrounding area decompose the beans and produce important chemical compounds that make up the final taste and aroma of chocolate,” explains David Gopaulchan from the University of Nottingham. Due to this uncontrolled process, however, the finished chocolate products do not always have the same quality and the same taste profile. The manufacturers have so far largely been unknown which microbes the cocoa fermentation and how they met the beans.
Chocolate taste is microbial teamwork
Researchers around Gopaulchan have now examined in more detail which microorganisms are involved in the cocoa fermentation. To do this, they took rehearsals from the cocoa beans of three different farms in Colombia and analyzed by DNA sequencing, which microbes live on it. In addition, they examined which molecules the microbes produce exactly and what influence the temperature and pH value have on these products and the taste result during the days of fermentation.
The analysis showed that several bacteria and fungi work together at the same time or one after the other in the cocoa fermentation. Among the microbes were primarily Erwiniaceae and Acetobacteraceae bacteria and saccharomycetaceae mushrooms. Their enzymes convert the cocoa raw materials into different sweet, fruity and hearty aroma substances. The temperature increases during the fermentation process and drops the pH in the beans, which in turn influences the further work of the microbes. The combination of their respective enzymes, metabolic pathways and products results in the unique taste profile of the chocolate made from the beans, as the team explains. Professional food custodians confirmed that differently fine tastes arise. For high-quality noble chocolate with little bitter substances, a special composition of the microbe community on the cocoa beans is therefore required.
Chocolate production for the first time
Gopaulchan and his colleagues then imitated this natural process in the laboratory. To do this, they selected a corresponding microbial community consisting of five types of bacteria and four types of mushrooms and had these cocoa fermented under controlled conditions. With this recipe, the researchers were actually able to produce noble premium chocolate with a fine taste profile-regardless of the origin of the cocoa beans. The professional tasters and laboratory analyzes confirmed that these chocolate contained the same aromas, like naturally produced noble chocolate.
With the knowledge, chocolate production could be optimized in the future by adding the desired microbes to the cocoa of any origin. So reproducibly high -quality chocolate with constant quality and taste would be created. This is a “change of spontaneous, uncontrolled fermentation towards a standardized, scientifically sound process,” said Gopaulchan. Just as beer and cheese have been fermented under controlled conditions for a long time, this could also apply to chocolate in the future.
Source: David Gopaulchan (University of Nottingham) et al.; Nature Microbiology, DOI: 10.1038/S41564-025-02077-6
