Sun-cured tobacco, Bastam, Iran Curing and subsequent growing old let to the slow oxidation and degradation of carotenoids in tobacco leaf. This creates particular compounds from the tobacco leaves and offers a sweet hay, tea, rose oil, or fruity aromatic flavor that contributes for the "smoothness" of your smoke. https://broadfar.com/nuso-heated-tobacco-smarter-alternative-to-traditional-smoking/