Physicists explain how cheese rosettes form

The Swiss cheese known as Tête de Moine or “monk’s head” is served in a peculiar fashion. A specially designed blade scrapes off thin slices of the cheese wheel, rotating around its surface like a hand of a clock. This process forms thin, frilly cheese rosettes.

Now, scientists have uncovered the physics behind these cheese flowers. It all comes down to the friction between the cheese and the blade, physicist Jishen Zhang and colleagues report in a paper accepted to Physical Review Letters.

“I’m absolutely not somebody who is very specialized in cheese cutting,” says Zhang, of ESPCI Paris. He was investigating wrinkles in other materials, including torn plastic and paper, when a cheese-loving colleague drew his attention to the flowers.

When a piece of plastic is ripped in two, wrinkles can appear due to the plastic stretching as it tears. At the edges, the plastic is longer than it is far from the rip. This length mismatch forces the plastic to take on a rippled texture.

In cheese, Zhang and colleagues discovered, the opposite is happening. Measurements and images of cheese-scraping in the lab revealed that the cheese gets compressed as it is cut. And, importantly, the cheese is compressed more at the center than at the edge. That’s because there’s less friction between the blade and the cheese’s hard rind, compared to where the blade meets its soft innards. The resulting length mismatch between the compacted center of the scraped cheese and its edge creates a ruffly flower.

To test their conclusions, the researchers removed the rind encircling the wheel, then put the now-uniform cheese back under the rotating blade. The friction between the blade and the cheese no longer varied across its surface, resulting in cheese flakes that were flat, rather than flouncy.

The flower shape impacts the flavor, Zhang says. The shape allows the cheese to mix with the air, releasing its aroma. Zhang tried cutting the cheese into cubes, and the taste wasn’t the same.

As for the florets’ flavor: “I have to say, it’s tasty,” Zhang says. But there’s a hazard to experimenting with cheese. He overdid the taste tests during the course of the experiments, spoiling the cheese’s appeal. “I used to like it, but since I ate a lot … I need to take a rest.”