Sunlight-cured tobacco, Bastam, Iran Curing and subsequent getting old permit for the slow oxidation and degradation of carotenoids in tobacco leaf. This creates specified compounds from the tobacco leaves and provides a sweet hay, tea, rose oil, or fruity aromatic taste that contributes to your "smoothness" of your smoke. https://broadfar.com/non-combusted-cigarettes-a-safer-alternative-or-just-a-myth/