1 、By subjecting various untreated hardwoods to processes described as (a) controled burning,(b) dry distillation at appropriate temperatures,usually between 300 and 800°C,(c) treatment with superheataed steam at temperatures,usually between 300 and 500°C,and condensation and capturing of those fractions which have the described flavor potential.2 、By applying fuether isolation techniques to the fractions obtained under 1.[item]1 in order to retain only the flavor wise important fractions or components.By compounding chemically defined flavoring substances. Smoke flavors should contribute no more than 0.03ppb 3,4-benzopyrene to the final food product.