Why are the bottoms of cooking utensils blackened?

Why are the bottoms of cooking utensils blackened?

PROF WAQAR HUSSAIN

            There are three main reasons to blacken the bottoms of cooking utensils (not of copper).

First, the black surface absorbs more heat as compared to clean surface. The absorption of heat depends upon the surface. According to Prevost Theory of Heat Exchange: “Every body emits radiation continuously to its surroundings at the rate which depends only on the nature of its surface and temperature and at the same time 

it receives radiation from its surroundings at the rate depending on “the surface” and the temperature of surroundings.” So it is the economical practice to blacken bottoms of utensils to efficiently absorb maximum amount of heat. It not only saves fuel but also reduces cooking time.

              Now the question arises why copper utensils are not turned black. It is due to fact that copper oxidizes in presence of oxygen to form brownish black copper oxide. If it is not polished away copper oxide reacts with CO₂ to form green colour copper carbonate.

Second, bottoms are turned black for aesthetic reason as the fire emits black carbon particles especially yellow flame that blackens the bottom. Imagine for a moment, that the entire utensil has glitter but bottom has ugly black patches! When you yourself started to blacken the bottom, it became a normal, routine practice and soon people accustomed to it. It became normal for the eyes, acceptable for the society and developed as a decorative practice; abnormality turned to normality.

Third, people in some part of Asia are superstitious. There have a concept of “Evil Eye” which they believe to ruin the object on which it gazes. Especially in rural area, this concept is deep rooted. Further, it is more common in women than men. So, for this reason also, the village women started coating black their utensil to ward off evil eye for the safety of their cooked food. For them black colour dispels wicked eye. Even today, many people in Asia, place the handi( a cooking pot made of clay roasted in furnace with black underneath) on the top of roof of their newly constructed building to keep at bay evil eyes. Some time, mothers make a mark black mole on the faces of their beautiful kids to protect their children against evil eye.