Virginias, Va/Pers and VaBurs will age the best, they tend to develop a sugary bloom that really sweetens the smoke. Balkans age well, but can mellow out over time, sometimes a lot, sometimes not much at all, depends on the blend and the tin! Straight Burleys remain pretty much the same over time, some will get sweeter but most will not change much. Aromatics can lose their topping over time, not always, but often they are reduced in flavor with age. Regular strength English blends should mellow a bit over time, some will lose their punch entirely, but if you are lucky and choose wisely they can become SUBLIME....often giving you a smoke that is unavailable without the benefits of time.
