As a wine collector friend of mine said, if he had a Coravin his cellar would be full of half-drunk bottles of Petrus and Romanee Conti.

I haven't noticed enough of a change in open bottles of whisky to bother, but I wonder if what we use for wine in our household would work. The argon sprays buy you a few extra days at best IME with wine; what we do is pour off the excess into a clean 250ml glass soda bottle, leaving a tiny bit of headspace, then apply a bottle cap with a handheld cap crimper.

This keeps the wines good for months on end.

I can only imagine it would work great with whisky, too, although then you have a bunch of soda bottles you hopefully labeled...

I don't know. I'm just a little squeamish about adding anything to my wine or scotch bottle. I know the point is that the gas is inert, but it still seems weird to me.

Well of course distilled products don't oxidize. I too have a few sizes of small bottles to accommodate whatever fraction of the wine we didn't finish.

I'd be leery of argon. It's heavier than air and will kill you if you fill your lungs with it.

What makes you say that?

Everything IME and everything I've read. I have consumed odd stuff tthat won't sell that's been open for years many times, just to get it off the shelf of my bar. They all tasted fine. Liquors above 80 proof are stable and won't change at all for over a year open and glaciely after that. I think the small changes after years are good. Whiskeys and Cognacs get a little sweeter and honeyed IMO.

I find Scotches and Cognacs does not have a flavorful change over long term opened bottle storage. I think it is very minor evaporation. I have been given some slow moving bottles by the in-laws to clear space for more profitable brands which still taste fine.

Oxidation in opened wine is a chemical change and flavour is affected mostly in a negative way.

Agreed that the biggest change in flavor in an opened bottle will be due to evaporation. Proper storage with the cork kept wetted is critical to minimizing evaporation IMHO.

There can be minor oxidative changes over time to even distilled spirits; obviously, the higher the proof, the less "stuff" there is to oxidize (as ethanol isn't going to suffer oxidation as part of aging). And with more headspace in the bottle, there's room for more of the interesting flavor compounds to evaporate into the air and leave the whisky itself... but again, this should be very minor compared to the kinds of changes you see in most wines.

and whatever causes wine to age in bottles, and liquor not to "age" in bottles.. (unopened bottles)

The pH of wine is far different and it still has enzymes working on it that are removed from spirits by distillation. Stuff above say 40° doesn't age much.

Oh, those wily Scots.....

Recently, after a favor for a friend of modest means, I was gifted with 6 bottles of Single Malt priced far below (I checked, about a discounted $20 for 750ml) the premium prices usually attached to any known Single Malts.

The 3 whiskys....

McGavin's Speyside
McGavin's Highland
Glen Moray Speyside.

Tried'em all. Akshuly, not bad, for $20, not bad at all, but I have a suspicion that's there's more at work than just $20 Single Malts.

As the taste and demand for Single malt whiskys has risen, literally skyrocketed in recent years, sales of "Blended" whisky has declined. As a result, across the industry, demand for the traditional low-end single malts purchased/utilized by blenders to produce the almost spectrum of familiar blends has dropped.

Never to be out-thought, those wily Scots are bottling malt distillates once relegated to inferior status as components in "Blended Whisky" as lower priced "Single Malts" to utilize whisky in low demand, while attempting to fill the new craze for "Single Malts"

Could McGavin's and Glen Moray's bottling fall into this category?

I know nothing about MacGavin, but Glen Moray has had good
notices for decades, not including mine, which of the 1992
('10 bottling) reads "too much alcohol (almost rubbing) in
front; boiled sweets; vanilla."

indeed, and even big brands are creating/rearranging entry products

We 'Merkins are not raised on "Boiled Sweets" so I missed that flavor component, and I got a hint of more "Extract" than Vanilla itself, but the hard edge of alcohol in the Glen Moray was evident, reminding me of Cutty Sark and extremely popular Scotch 50 years ago (but less so today).

For $20 after discount, Glen Moray is certainly better than most of those "Well Brands", the blends on the bottom shelf at the liquorateria/Tienda Booza