The few times I've had a chance to try varietal Norton/Cynthiana (the wines are commercially unavailable in Ontario) I've found some with aromas reminiscent of Vitis riparia-/rupestris-based (so-called "French-hybrid") reds. In my years of studying Ontario reds made from the common riparia-derived hybrids, I have come to understand the so-called "hybridy" aromatic palette as comprising aromas that can be essentially described as toasted grain, toasted coffee bean, charred coffee bean or coffee roastery, smoky buckwheat (think here of Eastern European kasha), and smoky hickory. At times, I have also gotten a vegetal leafiness in certain hybrid reds such as Baco and Foch and an aroma that's sort of grassy but in no way similar to the bell-pepper pyrazines that we associate with underripe Cabernet, for instance.
The ability of Vitis aestivalis to produce aromas reminiscent of riparia-based hybrids does not come as much of a surprise to me: both species are native to North America, so it could follow that in addition to sharing excellent cold hardiness and disease resistance they might also share certain innate chemical compounds that can produce those unique aromas when vinification takes place. I would also surmise that the presence of those compounds in Norton proper and riparia-derived interspecific crosses might be indicative of some kind of common evolutionary starting point. Some folks have noted occasional hints of methyl anthranilate in certain Nortons too (heck, even in Pinot Noir!), so here again the case is made for the possibility of an interspecific commonality.
As a wine enthusiast living in North America, I have come to understand these particular aromas not as flaws but as bespeaking the soul, if you will, of the archetypal native American red wine. I see those aromas decidedly as features, not as flaws. These charry/grainy aromas can only be understood as flaws when juxtaposed against a vinifera-oriented paradigm within which they have neither precedent nor meaning; taken as they are on their own, however, they are fully self-justified expressions of identity.
The established wine world uses vinifera as its yardstick, and therefore many palates are unattuned to the aromas in certain non-vinifera grape wines. Personally however, I am able to just as happily drink a Blumenhof Cynthiana and enjoy its charred-coffee-bean/woodsy aromas as I am able to enjoy a Pauillac or a Barbera for their individual characteristics. I can enjoy a good Barolo. I can enjoy a good Cab Sauvignon. I have been trying to understand, and feel that I do have a better understanding, of Pinot Noir in recent times. I can enjoy a Margaux or a Pauillac. BUT! - and here is the key - none of these wines reduces or cancels out my sincere interest in and appreciation of native varieties and hybrids, in which I find much to enjoy.
It is satisfying to seen an increasing number of people in cold-climate wine-growing circles converging in agreement as to the value of grape varieties that actually work in their climates and produce wines true to their origins.