Sun-cured tobacco, Bastam, Iran Curing and subsequent growing older let for the sluggish oxidation and degradation of carotenoids in tobacco leaf. This generates specific compounds during the tobacco leaves and provides a sweet hay, tea, rose oil, or fruity aromatic flavor that contributes into the "smoothness" in the smoke. https://broadfar.com/oraco-global-trends-in-heat-not-burn-products/