To paraphrase W. C. Fields, who was the first to add water to bourbon for the purpose of controling the proof--as opposed to "rectifying" it to extend profits? When bourbon was sold directly from the barrel (the real first single barrel, barrel proof?) the proof would obviously vary. My understanding is that BIB laws were implemented because too many unscupulous people were not only watering their bourbon but adding all sorts of other things to "improve" it. Old Forester was the first bourbon sold exclusively in bottles with a signed guarantee that you were getting the real thing.
Does anyone know at what point bourbon was sold at a deliberately pre-established proof? Obviously, every distiller had access to distilled water that could be used for that purpose. Who decided that it would be a good thing to offer 100 pf or 86 pf or whatever? And when did 80 become the "standard" proof?