Sunshine-cured tobacco, Bastam, Iran Curing and subsequent getting older let for that gradual oxidation and degradation of carotenoids in tobacco leaf. This produces specified compounds from 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/