Chocolate Manufacturing and Cocoa Processing Before cocoa can be made into chocolate, it goes through several steps of processing. Cocoa processing includes converting the beans into nibs, liquor, butter, cake and powder. Chocolate manufacturing includes the blending and refining of cocoa liquor, cocoa butter and various ingredients, such as milk and sugar.
Cocoa Processing Inspection and Cleaning First, the beans are inspected and thoroughly cleaned of any debris that may have fallen into the sacks, such as sticks, stones, or broken beans. Once the beans are cleaned, the processor has the option of roasting them before or after the shell is removed. The inside of the cocoa bean is called the nib. Generally speaking, chocolate manufacturers prefer to roast the beans before shelling them, while cocoa processors favor the nib-roasting process.
Roasting, Shelling, and Grinding Roasting the whole bean allows for more variety in the degree of roast and development of flavor, but requires beans of a uniform size, while nib roasting is more even and does not require uniform bean size. Roasting the nib directly also prevents migration of cocoa butter from the bean into the shell, which is discarded.
Once the beans have been shelled and roasted (or roasted and shelled, as the case may be), the nib is ground into a paste. The heat generated by this process causes the cocoa butter in the nib to melt, earning it the name “cocoa liquor.” The paste, further refined, may be sold as unsweetened baking chocolate. All cocoa products start with cocoa liquor, although the liquor required in the manufacture of chocolate has a different texture from the liquor required to make cocoa butter, cake and powder. Chocolate liquor destined for processing into cocoa butter and cake is refined to a very small particle size, while chocolate liquor for chocolate production need not be as finely ground.
Cocoa Butter and Cocoa Cakes The liquor is then fed into hydraulic presses that remove a certain percentage of the cocoa butter, leaving behind a cake containing from 6 to 24 percent of the cocoa’s initial butter. The extracted butter can be kept either in liquid or moulded form. The cocoa cake is either broken into smaller pieces (kibbled) and sold into the generic cocoa cake market, or ground into a fine powder.
Dutch Process The cocoa processor has the option of treating the nib or the liquor with an alkali solution (alkalizing), which reduces the acidity by increasing the normal pH factor from about 5.0 up to 8.0. This treatment is also known as "dutching", honoring the homeland of its inventor, C. J. Van Houten, who also developed the cocoa butter pressing method.
Alkalizing cocoa nib or cocoa liquor renders the powder darker; gives it a milder, but more chocolaty flavor, and allows it to stay in suspension longer in liquids such as milk.
Cocoa butter extracted from alkalized liquor is more pungent, with a less desirable odor and flavor, and must be deodorized and refined. It is then carefully blended with other cocoa butters, so that the final butter for sale has a consistent flavor, color and viscosity.
Chocolate Manufacturing To manufacture chocolate, cocoa liquor is mixed with cocoa butter and sugar. For milk chocolate, producers can add fresh, sweetened condensed or powdered milk, depending on the desired taste. In the crumb or flake process, liquor is blended with sugar and pre-condensed milk, or sweetened condensed milk. It is then dried on heated rollers to produce the flavor more typical of European chocolate or mixed with slightly acidified milk to produce the flavor customary in the United States.
After the mixing process, the blend is further refined to reduce the size of the milk and sugar particles. The mixture is then placed into conches—large agitators that stir the mixture under heat. Normally, cocoa butter is added to the mix at this stage, although some manufacturers add it during the original blending process.
“Conching” further smoothes the mixture. As a rule, the longer chocolate is conched, the smoother it will be. The process may last for a few hours to three full days, or even longer.
After conching, the liquid chocolate may be shipped in tanks or tempered and poured into molds for sale in blocks to confectioners, dairies, or bakers. It may also be converted into proprietary bars for sale direct to the consumer market.