Dunno about ‘scientifically detectable’ (although some differences would be bandied about for several years as to what makes a good liquor or what makes it rotgut), but speaking from experience: once you have tasted the truly fine ones... there really is no forgetting it. You will never mistake it for the cheap dregs ever again.
That’s what I tell people too.
The ultra-expensive stuff, tho, usually isn’t worth the delta above the top-shelf $50 to $150/bottle stuff.
For example, I’ve found in single malt whisky that aging the spirit more than 18 years really adds nothing in terms of taste or nose. Somewhere between 12 and 18 seems to be the optimum aging time. 25 year single malts cost substantially more, but IMO aren’t worth it.
Now, is single malt better than blended whisky, or stuff like Chivas? Oh yes.
That said, there are some very good American whiskeys (bourbons, mostly) which are very good for very reasonable prices. I’ve recently discovered Buffalo Trace, and I find it very drinkable neat. Only about $25/bottle. I’d put it up there against any $60/bottle single malt.
My introduced me to Breckenridge Bourbon. I love it.
I am mostly a vodka drinker.
I wasn’t a big fan of whiskey before but now I pick up a bottle for special occasions. Doesn’t last me long though. :(
https://www.breckenridgedistillery.com/hooch/awards/