Sunshine-cured tobacco, Bastam, Iran Curing and subsequent getting older let for that sluggish oxidation and degradation of carotenoids in tobacco leaf. This produces certain compounds during the tobacco leaves and provides a sweet hay, tea, rose oil, or fruity aromatic flavor that contributes into the "smoothness" of the smoke. https://broadfar.com/nuso-heated-tobacco-smarter-alternative-to-traditional-smoking/