Crushed cocoa beans with husks

When people think about chocolate making, they often overlook one important step—the winnowing process. Each cocoa bean is surrounded by a fibrous husk. When the cocoa pod is on the tree, this husk serves to protect the interior of the bean from animals that may break into the pods to eat the sweet pulp that surrounds each bean. When moist, this husk is soft and pliable, but once dry, the husk forms an almost impenetrable barrier—and one that must be removed in order to make a smooth chocolate at peak flavor.

After the beans have been harvested, they are fermented, dried, then shipped to the chocolate maker. When the chocolate maker receives the cocoa beans to make into chocolate, they are very hard, and the husk adheres to the bean with an iron-tight grip.

Husk Removal: Key to Quality

If the husk is not removed, the remains of the fermented pulp will end up being integrated into the final chocolate, creating an “off” flavor that is not easily removed from the finished chocolate without damaging its flavor.

Unfortunately, a few chocolate makers still integrate significant amounts of husk into their final chocolate. This occurs in one of two ways. First, there are those that integrate significant amounts of chaff and hope that nobody notices. In order to cover up the off-flavors imparted by the remains of the fermented pulp as well as the husk itself, a very heavy roast is used. This helps to disguise the flavor of the pulp, but unfortunately, it also destroys many of the more subtle flavors that are part of the cocoa bean itself.

Second, since government regulations on chocolate still allow for the presence of some husk (up to 1.75%), some chocolate makers will work to ensure that the maximum allowable amount of husk remains present. While this may only be fractions of a percent, when large amounts of chocolate are concerned, the fractions of a percent add up quickly. Since the husk is essentially free, this small percentage of savings adds up, creating an enormous cost savings.

For fine chocolate, however, adulteration with cocoa husk should not even be considered. The impact on flavor is too great. Furthermore, if shortcuts are taken in this very crucial step, it is highly likely that shortcuts will also be taken on other important aspects of the chocolate making process. The result is an inferior product.

Roasting

Roasted cocoa beans

When cocoa beans are roasted, several things happen. First, the fats in the cocoa bean husk melt. The fat that is in the husk of the cocoa bean is not the same as the cocoa butter contained in the bean, but it is closely related. After the fat in the husk melts, the cocoa butter in the bean begins to melt. The melting of the fat in the husk, as well as that in the bean, helps to loosen the husk from the bean itself. The dried cocoa beans contain about 10 percent water and this involves the final step needed to separate the husk from the bean. As the water heats, it turns to steam, and the steam rushes to the surface of the bean, blowing up the husk like a small balloon, separating the husk from the bean.

If the chocolate maker chooses whole-bean roasting, the roasting for flavor development and winnowing is one and the same. However, if the chocolate maker prefers nib-roasting for the cocoa beans, then the roasting for winnowing occurs first and is a separate process from the roasting used for flavor development. In this case, the roast for winnowing occurs at a high temperature for a short period of time. This blast of heat is enough to melt the fats in the husk and bean and to cause the water in the bean to vaporize quickly, separating the husk from the bean. The roast is not for a long enough period to start the Maillard and other reactions that are important for flavor development.

Breaking the Beans

After the roasting, the cocoa husk has separated from the bean, or at the least, it has been significantly loosened. Even so, the husk still surrounds the bean. In order to remove it, the beans must be broken. This may be done by using a series of rollers through which the beans pass. The rollers crush the beans, breaking them into pieces, along with the now brittle husk. The distance between the rollers must be tuned to allow for different sizes of beans.

The primary alternative to this procedure is to drop the beans into a series of rotating blades. The blades hit the beans, breaking them, then propelling them against a steel plate, further breaking the beans into pieces. These pieces are called cocoa bean nibs. No matter which method is employed, the end result is pieces of bean mixed with pieces of broken husk. Now that the husk that once surrounded the bean been removed, the bits of husk now can be separated from the bits of bean.

Winnowing the Wheat from the Tares

Okay, when we are dealing with cocoa beans, we aren’t dealing with wheat. However, when most people think of winnowing, the biblical reference to winnowing the wheat from the tares is the first thing that comes to mind. In ancient times, wheat would be thrown into the air on a windy day. The wind would blow away the light chaff (the paperlike coating around the wheat), and the heavier wheat would fall straight down and be caught on a mat.

Art with our winnowing machine

This ancient technique is not far from that used today. The husk that surrounds the cocoa beans is as thin as paper and very light. By contrast, the cocoa bean nibs are heavy—and this is the key to separating the two. The basket that was once used in ancient times to throw wheat into the air is today replaced by a winnowing machine, and the wind of ancient times is replaced by large fans capable of creating a veritable hurricane inside the winnowing machine.

The husk and nibs drop through the airflow, and the husk is blown away like confetti, leaving the bits of bean behind. The husk is blown into a separator that separates the husk from the airflow. The husk drops into a bin and the air goes into the … air.

Winnowing cocoa beans is more difficult than winnowing wheat, however. With wheat, all the grains are almost identical in size. In fact, anciently, grains were used as measures of weight for just that reason, giving us units of weight such as “grains” and “carrots” (from carob). By contrast, when a cocoa bean is broken, it breaks into pieces of a wide variety of sizes and weights. Because of this, it is difficult to tune the airflow to blow away the husks and leave only the beans.

Without a way to properly tune the airflow, it will be either too strong and blow away most all of the husk, leaving little bean nib; or the airflow will be too low, creating a high yield of nibs but also a high percentage of husk. As one might suspect, there is a better way to winnow cocoa beans.

The trick to solving the problem is to size the nibs and pieces of husk through the use of a series of screens with holes of varying sizes. Typically between five to seven screens are used to classify the bits of husk and bean by size. When the pieces are sized in this way, it is highly unlikely that pieces of husk and bean of the same size will also be of the same approximate weight.

Cocoa nibs

The bits of husk and bean flow through or across the screens and then into chutes with individually adjustable airflows. The airflow in each chute blows the husk up, and out while the cocoa nibs fall into a receptacle.

While the cocoa bean nibs are carted away to make chocolate, cocoa powder, and other cocoa-based products, one may wonder what happens to the husk. This has been a source for debate for well over one hundred years. In the late 1800′s and early 1900′s, it was thought that the husk would make a good additive to animal feed. Unfortunately, because of the high levels of theobromine in cocoa husk, when this was tried, the animals promptly died. While theobromine is not toxic to humans (and in fact, it helps give chocolate some of its “addictive” properties), it is poisonous to most animals, especially poultry (such as chickens). For this reason, it has found only limited use in animal feed, since it must be given only in small quantities.

Today, cocoa bean husk is sold or even given away as garden mulch. For this, the husk is highly sought after. The husk is full of nutrients and has high concentrations of nitrogen, potassium, and phosphorous—all important plant nutrients. Its strong fibers help to break up the soil, and thus it is particularly useful in soils with lots of clay. When used to cover the soil, it helps to keep the moisture in and makes a beautiful ground cover. The best part, of course, is that it makes gardens smell of chocolate. What could be better than that?

Free at Last!

Handful of cocoa nibs
ready to be made into chocolate

After the beans have been roasted, crushed, and winnowed, the precious cocoa bean nibs are free at last of their bondage within the husk and can be used to make a whole variety of incredible delicacies. For example, they may be ground along with sugar to make chocolate, or pressed in hydraulic presses to make cocoa powder. The cocoa nibs may even be used by themselves for cooking. Cocoa nibs make wonderful in chocolate chip cookies or even on a salad with orange slices and citrus vinaigrette. Most likely (and most importantly), the nibs will be used to make chocolate. If the craftsman who is working with the nibs takes care with roasting, winnowing, refining and conching, the cocoa nibs can meet their full flavor potential as part of an incredible chocolate.