All About Cacao Fermentation

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 underappreciated both by the public and the farmer alike. However, to the artisanal chocolatier, proper fermentation is critically important.

Chocolate made from unfermented beans does not have the body and richness as chocolate made from fermented beans. Chocolate does continue to be made from unfermented beans in parts of Mexico and Central America for use in traditional dishes. 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 fermentation only because that is what the market demands without fully understanding what improper 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 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 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 fermentation boxes or "sweatboxes." The sweatboxes 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. 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 fermentation.

The fermentation and 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, 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 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.

Sweatboxes

Overtime a number of different types of sweatboxes have been used. Thankfully, the techniques for building them continue to improve as do the techniques used to get a consistent fermentation.

Just a Hole in the Ground

One of the most traditional methods used up through the beginning of the 1900s to ferment the beans was simply to dig a small hole and place the beans in it. The beans were then covered with banana leaves to trap the heat generated by fermentation. Thankfully, this process is not used today to any great degree. The results were inconsistently fermented beans; and the mucilage coating liquefied and pooled instead of draining as it fermented, causing additional quality problems.

Wooden Canoe

Well, it isn't a real canoe but it looks like one. With this type of sweatbox, the beans are stacked into what looks to be a wooden dugout canoe. Unlike a canoe, though, there are small holes in the bottom through which the white mucilage coating can drain as the beans ferment. The beans are covered with banana leaves or a similar coating to help keep the heat in. Periodically, the beans are stirred with long wooden stirring poles. Not many of these remain, and this method of fermentation is disappearing. It would not be surprising if this technique traced its way back to the Mayans or Olmecs.

Stacked Sweatboxes

One of the earliest "industrial" techniques of fermenting cacao is to build a set of boxes, each box set on top and to the side of the next, creating in effect a set of stairs. Holes in the bottom allow for drainage as well as air circulation. The fermenting starts with the beans being hauled up and emptied into the boxes on the top level. As the cocoa bean fermentation continues, the beans are removed from the bottom box and then dried. The beans in the next higher box are shoveled into the bottom box, this turned and aerated them. The process continues up to the top box where new beans are then added. This happens once or twice a day depending on what the fermenting requirements are.

Modern Sweatboxes

New Fermentation Boxes

Today, boxes about four feet square and four feet tall are built out of a wood that is conducive to fermentation. (The wood of choice is red cedar.) Each box contains approximately one ton of beans. As with the stacked sweatboxes, holes in the bottom allow for aeration and drainage. The beans are shoveled from one box to the next with either wooden shovels or buckets. Long sticks are used to break up any clumps of beans and ensure that the beans are free flowing and are able to get plenty of air while they are fermenting.

In a common variation of this that often occurs at the co-op level, the boxes are fitted with steel frames. These allow for the boxes to be lifted into the air by an overhead hoist and then emptied into the next box. The dumping action breaks up the clumps of beans and allows fresh air to enter into the mix. The process of dumping one sweatbox into the next continues until the proper level of fermentation is reached.

Fermentation Times

The amount of time that the beans are fermented depends heavily on the type of bean. Criollo beans need a shorter amount of fermentation than do Forestero beans. This has much to do with Criollo's naturally milder flavor; not as much fermentation is needed to cut their harshness, compared to the harsher varieties of cacao. Fermentation times from five to seven days are typical.

When the fermentation is complete, the cocoa beans must be removed from the sweat boxes and carefully dried.

Consistency is a Virtue

No matter how the fermentation is performed, the key is consistency. The beans need to be fermented as perfectly as they can as well as be as consistently fermented as possible. While this task may seem easy, in fact it is very difficult. The farmers deal with literally tons of beans, and that makes stirring, fermenting, and processing consistently very difficult. It can be done, however. There are three classes of farms or co-ops. Some have poor quality beans but are able to ferment them well, some have good quality beans but are incapable of fermenting them in a suitable way. If a chocolate manufacturer is capable of finding a farm or co-op where the nexus of these come together such that they not only have good beans but also are capable of fermenting them in a way that does justice to these small jewels, then the chocolate manufacturer has truly found a prize from which great chocolate may be made.

Needless to say, at Amano Artisan Chocolate, we scour the world for the few places where these nexuses exist. They are few and far between, and we have to look very hard to find them, but we believe that the chocolate that comes from these few sources is well worth it.