Sunshine-cured tobacco, Bastam, Iran Curing and subsequent aging allow for the gradual oxidation and degradation of carotenoids in tobacco leaf. This generates selected compounds while in the tobacco leaves and provides a sweet hay, tea, rose oil, or fruity aromatic taste that contributes towards the "smoothness" with the smoke. https://broadfar.com/heated-tobacco-shaping-a-safer-sustainable-smoking-future/