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