Cocoa Fermentation — Bringing Magic to the Cocoa
After the farmers have harvested the cocoa pods from the tree, some of the most crucial work begins to make fine, high-grade chocolate. The beans must be carefully fermented to bring out the very best flavors. It is unfortunate that the process of proper fermentation is under-appreciated both by the public and the farmer alike. However, to the artisanal chocolatier, proper cocoa fermentation is critically important. Chocolate made from unfermented cocoa beans does not have the body and richness as chocolate made from fermented cocoa beans. Chocolate does continue to be made from unfermented beans in parts of Mexico and Central America for use in traditional dishes. Cocoa fermentation also helps remove the tannins present in the cacao bean. Depending on the study, the amount of tannins in each bean is between five and fifteen percent of the bean by weight. Tannins bring an astringent flavor to the final chocolate and must be removed. Other compounds within the cocoa bean also detract from the taste of the final chocolate that proper fermentation also helps to remove. While roasting and conching helps remove the tannins through oxidation and other processes, the fewer tannins that are in the bean to begin with, the easier it is for the chocolatier to achieve an optimal flavor profile. Rather than having to be concerned with how to best remove the tannins — processes that may hurt the end-flavor profile — the chocolatier is able to concentrate more fully on bringing out the optimal flavors from beans to make the best chocolate possible. Unfortunately, the farmer is in most cases not a chocolate maker. Because of this, many farmers perform the cocoa fermentation only because that is what the market demands without fully understanding what improper cocoa fermentation does to the final chocolate or what wonders proper fermentation may bring. The problem is compounded by the mass-market chocolate companies that purchase the beans without particular regard to the degree of cocoa fermentation or even how consistently fermented the beans are. Of course, at Amano Artisan Chocolate, we are careful to work with our growers to ensure that the optimal fermentation is performed on all the beans we buy.
The Cocoa Fermentation Begins
Each cacao pod holds approximately 40 beans, and they must be carefully removed from the pods to ensure that the beans are not injured in the process. Some farmers will use machetes to open the pods, but this can damage the beans and causes quality problems in the product during fermentation and roasting. Farmers who are more careful will quickly rap the cocoa pod on a rock or tree, and the pod will quickly and easily break open, allowing the beans to be scooped out without damage. When they are first removed from the pod, the beans have a white, mucilage-like coating around each bean. It is sweet and yet tart. It’s a bit like a very sweet lemon and is incredibly refreshing on a hot tropical day. This coating provides a food source for the bean as it germinates. It also provides the sugar needed as the basis for the fermentation process that each bean will undergo. The beans are scooped out of the pods and then collected together for fermenting in one or more cocoa fermentation boxes or “sweatboxes.” The sweatboxes used for cocoa fermentation may be located at the plantation or may be located at the local co-op, where the beans are mixed with beans from other local farms during and after fermentation. No matter the location of the sweatboxes, it is important that this happen as quickly as possible, since the beans begin to germinate as soon as the fruit has been picked. If the germination process is allowed to progress too far, the beans will turn bitter, and the bitterness cannot be removed with further processing. As with most organic material, fermentation begins almost immediately upon exposure to air. Cocoa fermentation is no different. Spores from naturally occurring yeasts (Saccharomyces) settle on the sugary beans and start to split the sugar into alcohol and carbon dioxide. The alcohol is split further into acetic acid by the same bacteria that are responsible for turning wine into vinegar, the Mycoderma aceti. The chocolate maker must later remove the acetic acid that is generated through cocoa fermentation.
The fermentation’s chemical changes occur both outside and inside the bean. The sweet mucilage-like coating on each bean spurs the fermentation that takes place outside the bean. Given the incredible amount of fermentation going on, the temperature rises quickly. In fact, during the cocoa’s fermentation temperatures can climb to 122F (48 C), so hot that if you were to put your hand into the sticky gooey mass of beans, you would not be able to leave it there for very long. On the second day of fermentation, the temperature reaches 113F (43 C), where the germ within the cacao bean dies from the heat, alcohol, and acetic acid. When the germ dies, important chemical changes begin as enzymes within the bean itself are released. These are important to the development of the chocolate flavor. The beans must also be rotated within the sweatboxes. This is normally done by transferring the beans from one sweatbox to another. In the process, if they are rotated too frequently, they will get too much oxygen, and the beans will become too hot and develop dark spots. On the other hand, if they are rotated too infrequently, the cocoa beans will ferment inconsistently, since the beans in the interior of the sweatbox will get less oxygen than those on the sides. As with most things, to get it just right requires an artist’s skill.