Sunshine-cured tobacco, Bastam, Iran Curing and subsequent getting old permit for the gradual oxidation and degradation of carotenoids in tobacco leaf. This creates certain compounds inside the tobacco leaves and gives a sweet hay, tea, rose oil, or fruity aromatic flavor that contributes on the "smoothness" on the smoke. https://broadfar.com/non-combusted-cigarettes-a-safer-alternative-or-just-a-myth/