A GC method has been developed for the determination of polyalcohols and sugars in aqueous extracts from green coffee beans, ground roasted coffee beans submitted to either conventional or torrefacto processes, coffee blends and soluble instant coffees. Bornesitol was detected in aqueous coffee extracts for the first time. Mannitol, myo‐inositol, mannose, fructose, galactose, glucose and sucrose have also been determined. Results seem to indicate that coffee manufacturing processes, such as roasting or decaffeination, do not affect the polyalcohol content. Coffee substitutes based on cereals, carob or chicory, have also been studied. The possibility to characterize their presence in coffee extracts was evaluated.