Weekend Argus (Saturday Edition)
If it looks and cracks like a tasty piece of chocolate, it probably is
TRICK or treat! With Halloween around the corner, children are about to collect bags full of sweets – including chocolate. Meanwhile, a group of researchers in the Netherlands has been experimenting with a method to make chocolate more of a treat.
While chocolate is delicious for many reasons, this study focused on how it cracks when it is bitten. “An aspect that I particularly like is its brittleness, and what it does when it breaks,” said researcher Corentin Coulais from the University of Amsterdam.
“We gave geometry to chocolate that would change the way it breaks”.
Giving it “geometry” involved using a 3D printer to layer 72% dark chocolate in various ways. Rather than creating a flat, solid chunk, the machine printed it into a simple S-shape, or zigzagged super-thin layers back and forth several times, or swirled it into increasingly complicated spirals. The resulting pieces were fed to 10 eager volunteers.
The crunchiest – while remaining easy to bite – was the chocolate swirled into fairly complicated spirals. It was also the top-tasting experience. “More crunchiness meant that people tended to like it more,” Coulais said.
The researchers also used a machine to crack the various shapes to see which was the most brittle. The general winner remained that spiral. However, the spiral iss not necessarily the best shape possible; it was just the best out of the few the researchers tested. “I'm sure there would be better ones if you searched more,” Coulais said.
So will chocolate soon be made differently? “It's too early to say,” Coulais said. He is working with organisations to see how it might be applied.
He is also involved in putting together a team to look at the physics of how things crack in materials other than chocolate – ones that might be used in vehicles, for example, to make them less dangerous when they crash.