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