Sun-cured tobacco, Bastam, Iran Curing and subsequent getting older allow to the gradual oxidation and degradation of carotenoids in tobacco leaf. This produces specified compounds in the tobacco leaves and offers a sweet hay, tea, rose oil, or fruity aromatic flavor that contributes for the "smoothness" from the smoke. https://broadfar.com/oraco-pioneering-a-smokeless-future-with-innovative-nicotine-delivery/