Physicists from the Czech Academy of Sciences have explained why food sticks to heated surfaces even when using a nonstick pan.
The authors studied the dynamics of liquid oil movement in Teflon-coated and ceramic-coated pans. They noticed that over time, a dry spot formed in the center of the pan.
The scientists found that heating from below establishes a temperature gradient of surface tension in the oil film from the center, where the temperature is higher, to the edges of the pan. This surface-tension gradient forms thermocapillary convection, which causes the oil to drip toward the edges.
“We have experimentally explained why food sticks to the center of the pan. It is caused by the formation of a dry spot in a thin film of sunflower oil as a result of thermocapillary convection,” said one of the authors of the study.
To avoid food sticking in the center of the frying pan, it’s important to use a frying pan with a thick bottom, reduce the heat, completely wet the surface of the pan with oil, or add more oil and stir the food regularly during cooking, according to the experts.