The black carbon soot on the bottom of pots previously used on an open flame can potentially inhibit the original conductivity of heat for cookware made of materials such as cast iron, aluminum, or granite. However, the extent of the impact depends on various factors, including the thickness and distribution of the soot layer.
Soot is a carbonaceous material that can act as an insulator, reducing the direct contact between the cookware and the heat source. This layer can impede the transfer of heat from the flame to the cookware, resulting in less efficient heat distribution and slower cooking times. Additionally, if the soot layer is uneven or covers critical heat-conducting areas of the cookware, it may further hinder the overall heat conductivity.
To maintain optimal heat conductivity, it is generally recommended to keep the bottom of cookware clean and free from excessive carbon buildup. Regularly cleaning the cookware with appropriate cleaning agents and methods can help remove the soot and ensure better heat transfer during cooking.