Why is there black ash in the hotel gas stove?

Phenomenologically speaking, smoke (including smoke produced by flame and smoke produced by cooking oil) rises and condenses into black substances called smoke or boiler smoke. Smoke can be made into ink or pigment.

In essence, when the combustion is insufficient, the carbon atoms precipitated at high temperature cannot combine with oxygen atoms, but will directly adhere to the bottom of the pot, the furnace head and so on, which is carbon deposition.

Whether it is burning coal or coal in a big kitchen, it is always burned insufficiently, which will inevitably form carbon deposits.