Conching processing

Rudolph Lindt invented the conching process, and additional step to decrease the average size of particles in the blend. 

Flavors, emulsifiers, or cocoa butter are often added during conching. The flavoring materials most commonly added in the United States are vanillin, a vanillalike artificial flavor, and natural vanilla (25) (see Flavors AND SPiCEs). Cocoa butter is added to adjust viscosity for subsequent processing. 

Liquefaction of the rolled product with more cocoa butter and lecithin occurs at 60°C (Fig. 14.28, right). This works mainly with pre-treated raw materials, such as crumb powder, where the flavor has already been formed and the moisture content has already decreased to less than 1%, providing a free-flowing mixture that allows for easy for pouring. This process saves several days of batch conching. 

Chemical bonding as a means of solidihcation is very widely observed in nature. Formation of sedimentary rocks, such as carbonate rocks, is an excellent example. Carbonate rocks are formed by the reaction of calcium oxide with the carbon dioxide from the sea water [14]. Sea organisms also use this process and construct seashells. The organisms that flourish in calcium-saturated solutions of sea water change the alkalinity of the solutions slightly and precipitate calcium carbonate, which is used to form protective shelters such as shells and conches. 

The refined chocolate mass is dry and powdery at room temperature and has a harsh, sour flavor. It is ripened before further processing by keeping it in warm chambers at 45-50 °C for about 24 h. Ripening imparts a doughy consistency to the chocolate and it may be used for the production of baking or other commercial chocolates. An additional conching... 

Efforts have been made to shorten this time-, energy- and space-consuming final refinement in conche pots. Processes have heen developed that are based on the separate pre-refinement of cocoa nibs or cocoa mass. The spray-film technique uses a cocoa mass with its natural water content or, in the case of highly acidic cocoa varieties, with the continuous addition of 0.5-2% of water. In a turbulent film with direct heat transfer, the cocoa mass is continuously dehumidified, deacidified, degassed, and roasted in counterfiow with hot air (up to 130 °C). For the final refinement, apart from the time-tested conche pots, newly developed intensive refiners can be used. They reduce the conching time to 8 hours. The development of continuously operated conche pots is also being expedited. 

Owusu, M., Petersen, M.A., and Heindal, H. (2011) Effect of fermentation method, roasting and conching conditions on the aroma volatiles of dark chocolate. J Food Process Pres 36,446-456. 

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