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