Very interesting, thanks. In the 1880's a writer from New York, who appeared to be a whiskey broker, wrote a book about whiskey blending. His best blends were mixtures of all-straight whiskeys with a small amount of fruit concentrate added, and he advised to barrel the blends and store them in the upper tier of the warehouse for at least 3 months. I think this is a bit like aging the whiskeys with the flavorings already added as you described. Here is the link:
http://www.pre-pro.com/recipe.htmYou can see that for his best blends, e.g., no. 17, he uses 3 all-rye whiskeys (all the names mentioned were well-known ryes), and grade no. 11 is two bourbons and one rye. His flavouring for no. 11 is prune juice (or prune wine as it was often termed), and for no. 17, a tea extract.
It is my view that a Maryland rye could have been made in the way no. 17 is made. Note that Jos. Fleishman, the author of the book, gives recipes how to make his tea, prune and other extracts. They are all spirit-based, too (i.e., GNS was added to help compound them).
His cheaper blends are the same approach as you see, and they differ, for the "bourbon blends", only in the amount of GNS - the more GNS to cut the blends, the less costly in the market were the blends (makes sense). It is basically the same for the better rye blends although some use coloring I see. His beading oil and bourbon flavouring and such were only used for the cheapest blends called Factious Whiskies.
His all-straight whiskey blends though would have used only aged bourbons or ryes, at least 2 years aged I believe but often more, plus a fruit essence (and not a lot as you see). E.g., you could compound a 2 year old bourbon, a 2 year old rye, and say an older bourbon, to get a balance, and add just a bit of one of the fruit extracts he mentions. Of course the older the whiskeys, the more barrel character. All his fruit essence recipes appear to be made from natural ingredients.
I believe that such blends were common all over the northeast U.S. at one time. With the diminution of distilling outside Kentucky, this kind of approach was still evident in Maryland which still had operating distilleries into the 1960's. In other words, I don't think the fruity style was peculiar to Maryland, I think it survived there longer than anywhere else. In Kentucky, the tradition both for bourbon and rye at least at the higher end was to sell the liquor straight. But in a sense blending of this type survived there too, via the blended whiskies made by all the surviving distilleries in KY (or most of them at any rate). A modern blended American whisky must have at least 20% straight whiskey as I recall, and the rest can be GNS, green whiskey (unaged bourbon mash) and other variants, plus permitted flavorings. This is really like the lower-end whiskeys Fleishman describes. Some Kentucky blends have more than 20% straight whiskey, one brand I know has 50%. That would be like a mid-range Fleischman blend except possibly without flavoring.
Gary