I was thinking of something that has been mentioned here on occasion, that some whiskey in the 1800's was made to be blended with lighter spirit and not to be sold on its own.
Whether or not the industry viewed it that way at the time, I was thinking about this in connection with some very interesting information reported by John Hansell in current Malt Advocate on how Crown Royal is produced.
25 whiskies are blended from 5 main types. (They differ otherwise by age and barrel type).
The 5 are all-column still produced but some are classified by the distillery as light and others heavy. The heavy ones present a broader congener range than the lightest types used. Probably they are distilled-out at a lower proof than those lightest whiskies.
One of the heavy whiskies is 96% rye. I would think this, or one of its variants, might taste something like Lot 40 (albeit Lot 40 was made by Hiram Walker) because Lot 40 is, but for any barley malt to assist in starch conversion, 100% rye-based (both malted and non-malted, apparently) and is either made in a pot still or at low proof to obtain a character similar to a pot still whisky.
Now, Lot 40 is a whiskey with a marked, perfumed, rye-oriented taste. At one time, maybe this kind of whisky had a good market here or in the U.S. (say early 1800's). It would have been quite young or even not aged so would have been even more pungent in taste than it is now.
Yet, the mashbills of U.S. rye whiskey ended up being (as we know) mostly "legal", where rye is not more than 51% of the mash except perhaps for Old Overholt and maybe one or two others. But the point being, corn is a part of the mashbills. Why? Because it lightens the taste. In fact in the form of bourbon, the mildness added by corn is taken further.
One of the Seagram's basic 5 types used to blend CR is a bourbon-type whisky with a high rye content (over 30% in fact). So Seagram uses some bourbon-type whiskey to blend, and may in the past anyway have actually added bourbon (U.S. bourbon) to its blends. Flavouring whiskies in Canadian usage either are made in-house for the purpose, or in some cases, straight rye or bourbon can (I understand) be imported and added to the whisky.
My sense is that by using a virtually 100% rye whisky which undoubtedly has great character (if not the kind of taste that might recommend itself to many people tasting it uncut - of course we are not given that option in Canada), Seagram may be solving more an engineering or throughput problem than anything else. In other words, maybe someone calculated (probably a long time ago) that if you add a very concentrated straight or straight-type whisky to a blend largely composed of light albeit aged whiskies, it is less costly to make a well-flavoured whisky than to distill at 160 proof or less from a mixed mash and age it many years.
Maybe the impetus in the mid-1800's, in other words, was not so much to change the taste of the mixed mash straight whiskies of the day, but to make the same kind of whisky in a less costly way. Maybe the first Seagram (and Hiram Walker, etc.) whiskies had some significant resemblance to the young straight ryes or bourbons of the day, in other words. Now, with the passing time, perhaps these more industrial types of whisky got lighter and lighter and ended up a different style from U.S. straight or straight-type (low proof, congeneric, relatively long aged) whiskey. But originally, maybe the development of the all-rye heavy whiskies and their use in conjunction with aged light whiskies (essentially aged GNS, probably, for the bulk of them) was a commercial expedient designed to maximise production at the lowest cost but not really intended to result in a different product from what people regarded as daily, potable whisky.
Gary