How the microbiomas of cocoa grains are essential to the most beautiful chocolate flavors

We could soon taste new types of chocolate after the discovery of mushrooms and bacteria that produce fruity and caramel notes from cocoa beans.

Chocolate is generally made by fermenting cocoa beans from the fruit of cocoa, drying them, roasting them and then raking them in a separate paste in cocoa butter and cocoa solids. These are then mixed in variable quantities with other ingredients to produce dark chocolate, milk or white.

During the fermentation stage, the microbes that come from the environment digest parts of the cocoa fruit and produce various molecules that contribute to the flavor of chocolate. In most cases, this brings dark and wooded flavors, says David Salt at the University of Nottingham, in the United Kingdom. But finer chocolate also has fruity flavors, often found in products sold by shop chocolate manufacturers, he said.

To discover which microbes can produce such flavors, salt and its colleagues have collected samples of fermentable beans of cocoa farms in Colombia. By analyzing the genetic material in the samples, they identified five bacteria and four mushrooms that were constantly found in lots of beans that produced fine flavor chocolate.

The team then took cocoa beans which were sterilized not to transport any other microbe and used the nine microbes to ferment them, before grinding the beans in a liquid, known as cocoa liqueur. A handful of chocolate taste experts then evaluated the liqueur and found that he had various fruity notes which were not present in liqueurs made from beans that did not have these microbes. “The addition of these microbes gave it citrus flavors, berry flavors, flowery flavors, flavors of tropical fruit and caramel,” explains Salt.

The results suggest that adding these microbes to fermentation mixtures could help cocoa producers improve the flavor of their cocoa and, in turn, to make more profit from their beans, explains Salt.

“We do not necessarily need to give them a sample of the nine microbes – there are almost certainly practical things that they can do to bias their microbiome in the right direction. For example, we could tell them that some of the mushrooms they need are outside cocoa pods, so why not do you a little from the outside of a pod?” he said.

However, all the microbes that produce fine flavors can differ in cocoa farms beyond Colombia, where differences in the climate, for example, can modify those that prosper. Other studies are necessary to explore this, explains Salt.

However, the study suggests that specific microbes can improve the flavor of chocolate and could even do it for types made with cocoa cultivated in the laboratory, explains Salt. In addition, this indicates that the selection of new microbial mixtures could even fully produce new types of chocolate, he says.