Solar-cured tobacco, Bastam, Iran Curing and subsequent aging allow for for your sluggish oxidation and degradation of carotenoids in tobacco leaf. This creates sure compounds during the tobacco leaves and gives a sweet hay, tea, rose oil, or fruity aromatic flavor that contributes towards the "smoothness" of your smoke. https://broadfar.com/oraco-global-trends-in-heat-not-burn-products/