Sunlight-cured tobacco, Bastam, Iran Curing and subsequent aging make it possible for for the sluggish oxidation and degradation of carotenoids in tobacco leaf. This creates sure compounds while in the tobacco leaves and provides a sweet hay, tea, rose oil, or fruity aromatic flavor that contributes for the "smoothness" https://broadfar.com/oraco-global-trends-in-heat-not-burn-products/