If you keep chocolate at the wrong temperature, it turns gray and crumbly. It all comes down to how cocoa butter molecules pack together. At different temperatures, they form six different crystal forms, and only one of them, form V, gives a glossy bar that snaps crisply and melts in your mouth. The other forms are that white bloom and crumbliness.

The authors of the study simulated the behavior of one hundred fat molecules as they were heated from 15 to 60 degrees. For each degree, they built a mathematical picture — a cloud of points where each point corresponds to the voids and connections between molecules. Then they measured how many holes of different sizes were in that cloud: small cavities, through-channels, and larger pockets. It turned out that form V had the fewest holes, and they were arranged in a particularly orderly way. It's like telling apart a sponge with even honeycomb from one with chaotic bubbles.

This approach could be useful in production: instead of expensive X-rays or lengthy tests, a quick computer analysis could tell whether the chocolate turned out right. For now, it's only a simulation, but it shows that mathematics can peer into the very heart of the sweet science.