It is recommended not to wait until the oil is too hot. Cooking oil burns to smoke, and the temperature reaches 200 degrees Celsius. At this temperature, not only the fat-soluble vitamins contained in oil are destroyed, but also various vitamins in food, especially vitamin C, will be lost when they contact with high-temperature oil. Edible oil will produce a kind of "acrolein" gas at high temperature, which has a strong stimulating effect on nasal cavity and eye mucosa, makes people cry, and even causes dizziness, nausea, anorexia and other adverse reactions.
Hot pot and cold oil are the best conditions.