Conche

A conche is a surface scraping mixer and agitator that evenly distributes cocoa butter within chocolate, and may act as a 'polisher' of the . It also promotes flavor development through frictional heat, release of volatiles and acids, and oxidation. There are numerous designs of conches. Food scientists are still studying precisely what happens during conching and why. The name arises from the shape of the vessels initially used which resembled conch shells.

When ingredients are mixed in this way, sometimes for up to 78 hours, chocolate can be produced with a mild, rich taste. Lower quality chocolate is conched for as little as six hours. Since the process is so important to the final texture and flavor of chocolate, manufacturers keep the details of their conching process proprietary.

Rodolphe Lindt invented the "conche" in Berne, Switzerland in 1879. It produced chocolate with superior aroma and melting characteristics compared to other processes used at that time. Legend has it that Lindt mistakenly left a mixer containing chocolate running overnight. Though he was initially distraught at the waste of energy and machine wear and tear, he quickly realized he had made a major breakthrough. Before conching was invented, solid chocolate was gritty and not very popular. Lindt's invention rapidly changed chocolate from being mainly a drink to being made into bars and other confections.

Lindt's original conche consisted of a granite roller and granite trough; such a configuration is now called a "long conche" and can take more than a day to process a tonne of chocolate. The ends of the trough were shaped to allow the chocolate to be thrown back over the roller at the end of each stroke, increasing the surface area exposed to air. A modern rotary conche can process 3 to 10 tonnes of chocolate in less than 12 hours. Modern conches have cooled jacketed vessels containing long mixer shafts with radial arms that press the chocolate against vessel sides. A single machine can carry out all the steps of grinding, mixing, and conching required for small batches of chocolate.

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