Sunlight-cured tobacco, Bastam, Iran Curing and subsequent growing old enable with the slow oxidation and degradation of carotenoids in tobacco leaf. This generates certain compounds from the tobacco leaves and provides a sweet hay, tea, rose oil, or fruity aromatic flavor that contributes to the "smoothness" of your smoke. https://broadfar.com/oraco-global-trends-in-heat-not-burn-products/