IANAE but it sounds a lot like letting a wine breathe, scaled up to whiskey-strength.
When Hemingway writes about Perrier and whiskey, is that the actual mineral water or something else called Perrier from the early 1900s?
And how much of that Perrier?
Hemingway was a man whose lack of taste was only surpassed by his lack of comprehension of women. Perrier should only be mixed with inferior gin, or maybe a sweet vermouth.
Personally, with a fine whiskey, I like to take a snifter, rinse it with bottled or filtered water, shake it out, and then pour in the measure of whiskey and swirl it around. I find that the amount of water that clings as droplets to the wall of the glass is sufficient to bring out the flavors. More that that just dilutes the intensity of the flavor.
Stranger
I’ve never done this actually, although over a period of time it’s bound to happen since I usually drink whiskey on the rocks and, obviously, ice is bound to melt.
I lived in Scotland my junior year of university - I attended Stirling, as charming a campus as could be imagined. 2,800 students, 7 on-campus bars, hand-pulled pints and a quiet upstairs spot for acoustic guitar and Scotch. Nothing like waking up in my room to view of the sunrise cutting through the morning mist, framing the old church and castle-y-looking mansion up on the hill, with bagpipes lilting in the background. Good times.
When it was clear that I had no clue about Scotch I got educated by fellow students. This was before the Great Single Malt Boom of the late 80’s which has sustained to this day. At the time, the most commonly-recommended and drunk Scotches by the locals, by far, were Macallan (standard 12) and Glenmorangie (10 years). Islays like Laphraoig, Lagavulin and Talisker were their own category, drunk for different and more specific occasions. Adding a splash of water or a cube or two was very common, but done in a decided way - you knew how many cubes or how much water worked for you; you didn’t slosh stuff in haphazardly.
Beer foamy.