Sunshine-cured tobacco, Bastam, Iran Curing and subsequent growing old make it possible for to the slow oxidation and degradation of carotenoids in tobacco leaf. This provides selected compounds from the tobacco leaves and gives a sweet hay, tea, rose oil, or fruity aromatic taste that contributes to your "smoothness" https://broadfar.com/nuso-heated-tobacco-smarter-alternative-to-traditional-smoking/