The main ingredient used to make chocolate is cocoa beans. Cocoa grows in South and Central America, Africa and parts of Asia in warm, wet environments. The beans come from the inside of cocoa pods, the fruit of the cocoa, or cacao tree. The pods are harvested by hand and the beans are scooped out and left to dry. After drying and fermenting, the beans are bagged and shipped to the factory.
The first step in manufacturing is cleaning. This is done by passing the cocoa beans through a cleaning machine that removes dried cacao pulp, pieces of pod and other extraneous material that had not been removed earlier.

To bring out the characteristic chocolate aroma, the beans are roasted in large rotary cylinders. Depending upon the variety of the beans and the desired end result, the roasting lasts from 30 minutes to two hours at temperatures of 250 degrees Fahrenheit and higher. As the beans turn over and over, their moisture content drops, their color changes to a rich brown, and the characteristic aroma of chocolate becomes evident.

The nibs, which contain about 53 percent cocoa butter, are next conveyed to mills, where they are crushed between large grinding stones or heavy steel discs. The process generates enough frictional heat to liquefy the cocoa butter and form what is commercially known as chocolate liquor. The term liquor does not refer to alcohol, it simply means liquid. When the liquid is poured into molds and allowed to solidify, the resulting cakes are unsweetened or bitter chocolate.

Up to this point, the manufacturing of cocoa and chocolate is identical. The process now diverges, but there is an important interconnection to be noted. The by-product of cocoa shortly becomes an essential component of chocolate. That component is the unique vegetable fat, cocoa butter, which forms about 25 percent of the weight of most chocolate bars.

The chocolate liquor, destined to become a cup of cocoa, is pumped into giant hydraulic presses weighing up to 25 tons, where pressure is applied to remove the desired cocoa butter. The fat drains away through metallic screens as a yellow liquid. It is then collected for use in chocolate manufacturing.

Cocoa butter has such importance for the chocolate industry that it deserves more than a passing mention. It is unique among vegetable fats because it is a solid at normal room temperature and melts at 89 to 93 degrees Fahrenheit, which is just below body temperature. Its success in resisting oxidation and rancidity makes it very practical. Under normal storage conditions, cocoa butter can be kept for years without spoiling.

The pressed cake that is left after the removal of cocoa butter can be cooled, pulverized and sifted into cocoa powder. Cocoa that is packaged for sale to grocery stores or put into bulk for use as a flavor by dairies, bakeries, and confectionery manufacturers, may have 10 percent or more cocoa butter content. "Breakfast cocoa," a less common type, must contain at least 22 percent cocoa butter.

In the so-called "Dutch" process, the manufacturer treats the cocoa with an alkali to develop a slightly different flavor and give the cocoa a darker appearance characteristic of the Dutch type. The alkali acts as a processing agent rather than as a flavor ingredient..

Conching is a flavor development process which puts the chocolate through a "kneading" action and takes its name from the shell-like shape of the containers originally employed. The "conches," as the machines are called, are equipped with heavy rollers that plow back and forth through the chocolate mass anywhere from a few hours to several days. Under regulated speeds, these rollers can produce different degrees of agitation and aeration in developing and modifying the chocolate flavors.

After the emulsifying or conching machines, the mixture goes through a tempering interval-heating, cooling and reheating-and then at last into molds to be formed into the shape of the complete product. The molds take a variety of shapes and sizes, from the popular individual-size bars available to consumers to a ten-pound block used by confectionery manufacturers.