Sunlight-cured tobacco, Bastam, Iran Curing and subsequent getting older let with the slow oxidation and degradation of carotenoids in tobacco leaf. This creates certain compounds within the tobacco leaves and offers a sweet hay, tea, rose oil, or fruity aromatic taste that contributes to your "smoothness" of your smoke. https://broadfar.com/nuso-heated-tobacco-smarter-alternative-to-traditional-smoking/