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