Sun-cured tobacco, Bastam, Iran Curing and subsequent getting old allow for the gradual oxidation and degradation of carotenoids in tobacco leaf. This produces particular compounds within the tobacco leaves and gives a sweet hay, tea, rose oil, or fruity aromatic taste that contributes into the "smoothness" of the smoke. https://directory-webs.com/listings13151173/a-secret-weapon-for-tabacco