Great
chocolate is complex mix of science, study finds
University of Edinburgh
Scientists have uncovered the
physics behind the process – known as conching – which is responsible for
creating chocolate’s distinctive smooth texture.
The findings may hold the key to
producing confectionary with lower fat content, and could help make chocolate
manufacturing more energy efficient.
Edinburgh researchers studied
mixtures resembling liquid chocolate created using the conching process, which
was developed by Swiss confectioner Rodolphe Lindt in 1879.
Their analysis, which involved
measuring the density of mixtures and how they flow at various stages of the
process, suggests conching may alter the physical properties of the microscopic
sugar crystals and other granular ingredients of chocolate.
Until now, the science behind the
process was poorly understood.
Smooth texture
The new research reveals that
conching – which involves mixing ingredients for several hours – produces
smooth molten chocolate by breaking down lumps of ingredients into finer grains
and reducing friction between particles.
Before the invention of conching,
chocolate had a gritty texture. This is because the ingredients form rough,
irregular clumps that do not flow smoothly when mixed with cocoa butter using
other methods, the team says.
Physics insights
Their insights could also help
improve processes used in other sectors – such as ceramics manufacturing and
cement production – that rely on the mixing of powders and liquids.
The study, published in Proceedings
of the National Academy of Sciences, involved a collaboration with researchers
from New York University. The work in Edinburgh was funded by Mars Chocolate UK
and the Engineering and Physical Sciences Research Council.
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 confectionary product. By studying chocolate
making, we have been able to gain new insights into the fundamental physics of
how complex mixtures flow. This is a great example of how physics can build
bridges between disciplines and sectors.
Professor Wilson Poon School of
Physics and Astronomy