Cocoa conching

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. 

Control of the polymorphic forms in cocoa butter is further compHcated by the presence of other fats such as milk fat. The fat in a chocolate can be likened to the mortar between the bricks in a mason s wall. The soHd particles in a weU-conched chocolate bed down better than the soHds in a coarsely refined and poorly mixed one (30). 

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. 

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. 

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