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 Pollard with Amano's antique winnowing machine

Amano’s Winnowing Machine along with Amano’s founder, Art Pollard. It was built in the 1920’s or 1930’s and refurbished at Amano’s factory.

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.

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.

Cocoa Nibs

Cocoa Nibs

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.

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.

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