The science behind smooth chocolate

Researchers have found that a 140-year-old mixing technique, called conching, is responsible for giving chocolate its smooth texture. The findings could help produce confectionery with lower fat content and make chocolate manufacturing more energy efficient.

A team led by the University of Edinburgh studied mixtures resembling liquid chocolate created using the conching process, which was developed by Swiss confectioner Rodolphe Lindt in 1879. Conching involves mixing ingredients for several hours, but the researchers wanted to better understand the science behind it.

They found conching may alter the physical properties of the microscopic sugar crystals and other granular ingredients of chocolate. According to the researchers, the process produces smooth molten chocolate by breaking down lumps of ingredients into finer grains and reducing friction between particles.

Chocolate previously had a gritty texture because the ingredients form rough, irregular clumps that do not flow smoothly when mixed with cocoa butter using other methods, the team said.

“We hope our work can help reduce the amount of energy used in the conching process and lead to greener manufacturing of the world’s most popular confectionery product. By studying chocolate making, we have been able to gain new insights into the fundamental physics of how complex mixtures flow,” said Professor Wilson Poon of the University of Edinburgh’s School of Physics and Astronomy, who led the study.

The study was published in Proceedings of the National Academy of Sciences.

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