To make fried rice like a pro, use physics.

Chefs typically toss fried rice from their woks into the air before catching it again. Launching the rice and its fixings allows the food to cook at a high temperature without burning, essential for creating the tastiest stir-fried fare. Now, using video of five chefs in Chinese restaurants, physicists have analyzed the repetitive movements used to toss the rice.

These chefs made a specific set of motions that repeated about three times a second, the researchers report February 12 in the Journal of the Royal Society Interface. Each repetition includes sliding the wok back and forth while simultaneously rocking it to and fro, using the rim of the stovetop as a fulcrum.

Cooking fried rice like a pro requires tossing it in the air to avoid burning. Physicists analyzed details of chefs’ movements and report that sliding and rocking motions repeat about three times a second, launching the food from a wok. Blue lines track the edges of the pan, with the left side moving clockwise and the right side counterclockwise. The red line notes the motion of the wok’s center.

Similarly complex maneuvers come into play when cooking other foods: Tilting and rotating the pan is necessary to get smooth, flat crepes, for example (SN: 6/19/19).

By simulating the trajectories of rice in a wok, the researchers hit on some key culinary tips. The rocking and sliding motions shouldn’t be totally in sync, otherwise the rice won’t mix well and could burn. And the wok’s movements should repeat rapidly. Moving the wok even faster could launch the rice higher, and might allow cooking at higher temperatures, and perhaps a quicker meal.

But faster shaking may be difficult for chefs to achieve. According to previous studies, chefs at Chinese restaurants can struggle with shoulder pain, and rapidly shaking a wok could be part of the problem. The researchers suggest that a stir-frying robot could be built based on these results, taking the weight off chefs’ shoulders.