The label describes Cordial-Médoc liqueur as being, “Prepared with superior products, allied with exquisite fruit and brandies specially selected for their fineness and aroma” [my translation]. The bottle says “depuis 1878,” but I can’t find Cordial-Médoc liqueur in any English-language drink books from before prohibition. No matter when it may have first been produced, it is fading away right now. Jourde is apparently not making the stuff anymore, and the remaining stocks are all that there will be. Since it is an ingredient that I have found in books (especially Tarling’s 1937 The Café Royal Cocktail Book), I thought that I would get a bottle of it.
It tastes to me like it might be raspberry eau-de-vie blended with brandywine and with some herbal accents added at some point during manufacture. I would think of it as being mostly high-quality raspberry-flavored brandy liqueur with a little something extra. It is quite good. Nothing about this liqueur overwhelms the palate, and to enjoy its subtle-but-varied flavor I should think it would be best served neat (as an after-dinner cordial), or perhaps as an accent to an-otherwise very plain mixed drink.
If I had to create a substitute for Cordial-Médoc liqueur using things that can be reliably found, I would experiment with mixing raspberry eau-de-vie with Cognac brandy, sugar syrup, and just a touch of a non-bitter herbal liqueur (such as Bénédictine). I might even try a more simple blend of Cognac brandy, crème de framboise and Bénédictine — but I suspect that this would produce something noticeably sweeter than the original.
If I find an analogous formula, I will share it.