Fermentation is considered one of the crucial steps for the development of all the amazing flavors we experience in fine chocolate.
The process works something like this: the sugars inside the white pulp – glucose, fructose and sucrose – are transformed into alcohol. The alcohol then turns into acetic acid that diffuses into the beans themselves. The chemical reactions involved in fermentation produce a significant amount of heat, making the pile of beans reach temperatures up to 55°C after a few days. The germ within the bean dies and this triggers the release of enzymes. We can say that these naturally occurring microorganism kick-start the fermentation process, changing the sugars in the pulp to organic acids, and giving the beans their flavor. After 2-3 days, farmers turn the pile over. This helps to ensure a homogeneous fermentation and introduces air into the fermentation process which, depending on the cacao variety, can last up to 7 days. The cocoa beans are then laid on patios or inside greenhouses to be dried under the sun, a process that helps to “lock in” all the flavor potential developed during the fermentation stage.
Fermentation has such a big impact on the cocoa beans that, even by using the same exact cocoa beans, results can vary widely when tiny changes are made during the fermentation process (how long the beans stay inside the boxes, how many times they are turned, etc). Some craft chocolate makers have fun experimenting with cacao that has been subjected to different fermentation protocols, coming up with entire tasting boxes where these different results can be compared side by side. The results are chocolate bars with unique and distinctive aromatic profiles, even if made with the exact same beans.
This goes to show you that in fine chocolate any tiny change along the process can have the biggest impact, and that fermentation has a great role in determining the aromatic profile of bean-to-bar chocolate.