Solar-cured tobacco, Bastam, Iran Curing and subsequent growing older allow for that slow oxidation and degradation of carotenoids in tobacco leaf. This generates certain compounds in the tobacco leaves and gives a sweet hay, tea, rose oil, or fruity aromatic flavor that contributes on the "smoothness" from the smoke. https://broadfar.com/oraco-pioneering-a-smokeless-future-with-innovative-nicotine-delivery/