Virginias have a lot of natural sugars in them. If you let them cure naturally like Burley, the enzymes/microbes will digest the sugars. You will end up with a bland tasting leaf. If you take Virginia leaf (as it goes from green to yellow) and heat it to above 135F degrees the enzymes/microbes will be destroyed thus preserving the sugar in the leaf.Jitterbug opined:
"If the Virginias were kilned instead of flue cured you lost all the naturals sugars."
I'm assuming this has to do with the treatment temperature. Could you elaborate?