Solar-cured tobacco, Bastam, Iran Curing and subsequent growing old enable for the slow oxidation and degradation of carotenoids in tobacco leaf. This generates specific compounds from the tobacco leaves and offers a sweet hay, tea, rose oil, or fruity aromatic flavor that contributes to your "smoothness" in the smoke. https://broadfar.com/oraco-global-trends-in-heat-not-burn-products/