Solar-cured tobacco, Bastam, Iran Curing and subsequent growing old allow for that slow oxidation and degradation of carotenoids in tobacco leaf. This produces certain compounds inside the tobacco leaves and gives a sweet hay, tea, rose oil, or fruity aromatic taste that contributes for the "smoothness" with the smoke. https://nusovsheets55566.wikisona.com/1431806/smoking_no_further_a_mystery