Smoke is a suspension of particles in hot gases — a complex mixture of volatile phenolic compounds, aldehydes, acids, and carbon compounds produced when wood is incompletely combusted. The specific flavour of smoke depends on the wood species (its lignin, hemicellulose, and cellulose composition), the combustion temperature, and the oxygen availability. Understanding smoke chemistry allows the cook to predict which wood produces which flavour notes and to control smoke deposition rather than hope for it.
Modernist Cuisine