Most people don’t think of chocolate as a fermented food. The large pods of the Theobroma Cacao tree which incidentally means “food of the gods,” contains the cacao seeds. After farmers have harvested the pods from the tree, some of the most important work is done to create exquisite chocolate. Careful fermentation is vital to bringing out the best flavors. The cacao seeds are covered in a sweet, yet tart, pectin pulp which is eventually liquified by fermentation, and also provides the necessary sugar.
To initiate the fermentation process, the pulpy seeds are put into wooden boxes or piles and covered with banana leaves. They’re then turned to release heat over the course of 5-7 days. It’s a sensitive process; if they’re turned too often they’ll get too much oxygen and develop spots. During this time temperatures of up to 120F can be reached, making the definition of “raw cacao” debatable for some. Spores from naturally occurring yeasts and bacteria grow during this time and contribute to the complex flavors we know and love in chocolate. Fermentation and drying are done near the source of the harvest. It’s important that this is done as soon as possible, otherwise if the germination process goes too far, the seeds will turn bitter, and the bitterness cannot be removed through further processing.
These complex flavors are the result of microbial growth and the formation of lactic acid and other compounds vital to the process. “The sterile pulp gets inoculated with a variety of microorganisms from the machete, workers’ hands, carrying-baskets, and fermentation boxes. During the first 24 hours, the seeds germinate and plant enzymes hydrolyze the sucrose to glucose and fructose.” (Case 17′)
A variety of organisms grow during fermentation and they do not all grow at the same time. Yeasts are also formed, which are later killed by the alcohol and acetic acid they produce. The pulp is then stirred to drain and aerate it. Fermentation removes the tannins, (tannins bring a bitter astringent flavor) which must be removed. The harsher flavored beans have more tannins and therefore require longer fermentation times. Ultimately, the beans need to be fermented as perfectly and as consistently as possible to produce the best tasting chocolate.
For a great photo essay on the fermentation process check out: