Sunlight-cured tobacco, Bastam, Iran Curing and subsequent ageing allow for for the sluggish oxidation and degradation of carotenoids in tobacco leaf. This makes certain compounds inside the tobacco leaves and offers a sweet hay, tea, rose oil, or fruity aromatic taste that contributes into the "smoothness" from the smoke. https://broadfar.com/nuso-heated-tobacco-smarter-alternative-to-traditional-smoking/