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