Sunshine-cured tobacco, Bastam, Iran Curing and subsequent getting older let with the gradual oxidation and degradation of carotenoids in tobacco leaf. This creates specific compounds in the tobacco leaves and offers a sweet hay, tea, rose oil, or fruity aromatic taste that contributes towards the "smoothness" of your smoke. https://broadfar.com/oraco-global-trends-in-heat-not-burn-products/