Physics Reveals the Secrets Behind Chefs’ Skillet Stirring Techniques
Have you ever watched a chef make fried rice in a restaurant or on a street food cart? You’ve probably noticed how they skillet stirring techniques, right? Well, two engineers from the Georgia Institute of Technology School of Mechanical Engineering in the United States decided to analyze those movements to identify the most optimal way to make fried rice.
Hungtang Ko and David Lu conducted their research in five restaurants in China and Taiwan, observing experienced chefs with over 20 years of cooking experience. They used slow-motion video recordings to track how the chefs “tossed” the rice in the wok.
Harmonic Function Describing Cooking Motion
According to ScienceNews, the chefs executed specific movements, repeated about three times per second, as reported in the Journal of the Royal Society Interface.
Each repetition involved pushing the wok forward and backward while swinging it back and forth. The chefs used the edge of the stove as a pivot point.
From their analysis, the scientists derived a harmonic function to describe all the chefs’ movements while shaking the wok.
This equation represents the kinematic shape of the wok, including the trajectory of the mixed rice and rice grains that fly out of the wok. And overall, the chefs’ movements were found to create a pendulum effect.
Naturally Optimized their Wok Movements
“First, the chef pushes the wok forward and rotates it clockwise to catch the falling rice. Then, the chef pulls the wok back while rotating it counterclockwise to toss the rice,” wrote the researchers, as quoted in Popular Mechanics.
The chefs naturally optimized their wok movements. According to the physicists, under varying cooking conditions, they maintained a consistent tossing frequency of 2.7 ± 0.3 Hz (N = 276).
The chefs tossed the wok in several successive cycles with an increasing frequency. In the initial variations, the wok moved more slowly. Eventually, the wok reached a stable condition.
Tips for Making Chef-Quality Fried Rice
Based on the simulated path of rice in the wok above, the physicists were able to deduce how to make fried rice like a professional chef. First, the swinging and sliding motions shouldn’t be entirely synchronized; otherwise, the rice won’t mix well and may burn.
“The wok’s movements should be repeated rapidly,” as noted by ScienceNews. A faster wok movement will propel the rice higher. This allows the chefs to cook at higher temperatures, reducing the time needed to produce a serving of fried rice.
However, it’s worth noting that executing the “shaking” motion rapidly might be challenging for chefs. Some previous research has indicated that Chinese restaurant chefs frequently experience shoulder pain. The quick wok movements could be one of the contributing factors.
The researchers suggest developing a frying robot based on their findings to ease the burden on chefs.