Interesting question, Roger. It actually made me think of Scotland, where I understand whisky cannot be called Scotch whisky if elements of its processing that have become traditional are not followed. For instance, I believe it would not be proper there to hasten or affect the maturation of Scotch whisky using pieces of wood suspended in barrels. (I haven't studied this but this is what I gather from reading the whisky press over the years). I would think though, if the Canadian rules applied in the U.S., that it shouldn't matter if sweet mash is used for bourbon. Because, I don't think the taste is significantly affected by that but it is more a process control matter, at least as I understand it. Even if the taste was somewhat affected, I don't think that should matter because it is still a method of fermentation and the main tastes still come from the grains and the barrels. You could make an analogy to the still, while continuous stills have become very common and indeed for generations, the pot still can also still be used to make bourbon as indeed B-F and others have shown in recent years. Also, I think sweet mashing was used for a lot of rye production into the 50's and 60's, at least in Maryland and Pennsylvania, so it is not really that long since it was last used commercially.