Knowing your Whisk(e)y

In the world of hard liquor, people usually have a general sense of what you're talking about when you mention a type of spirit-- at least from what I've noticed. For example, mention vodka and most people will assume you're talking about grain vodka (unless you're in an area where potato vodka, for instance, is generally assumed): Smirnoff, Grey Goose, Most Wanted, Bellevedere, etc. Even tequila generally refers to a pretty specific class of liquor, despite discussions of whether something is 100% agave (Patron, Don Julio, Cazadores Reposado) or not (Jose Cuervo) or if it has a worm in the bottle (Monte Alban). And even with spiced rum, rum flavors, and the like, "rum" also means a pretty specific thing.

However, say "whiskey," (with or without the "e") and you might as well have said "liquor." Okay, perhaps that is an exaggeration, but there is something to be said for the diversity found within the class of alcohol known as "whiskey." Everyone has a different idea, or no idea at all, of what "whiskey" refers to. If someone mentions whiskey, I don't entirely know what she's referring to. Is she referring to bourbon? Is she referring to blended whiskey? Or is she referring to scotch? If she's referring to blended, does she mean American or Canadian? And if she means scotch, is she including Irish whiskey? It isn't clear at all what "whiskey" is referring to except a broad category of liquor that includes American blended whiskey, Canadian whisky, bourbon, straight sour mash whiskey, scotch whisky, Irish whiskey, and possibly others.

Is whiskey a class of liquor, like rum, tequila, or vodka, or is it a meta-class of sorts that describes several classes of spirits (bourbon, blended, scotch, Irish)? At what point do you say that a class becomes a meta-class--or can it? Think about this before continuing.

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Allow me to elucidate here. So far I have stated or implied that rum, vodka, and tequila are sets (yes, I've switched from "classes" to "sets," just deal with it) of spirits, including some variations and many brands. For clarity's sake let us call these "tier 1" sets. I realize there are more spirits than what I've listed, but let's keep this from getting over-complicated.

Now, does whiskey, as a set, belong on tier 1 with rum, vodka, and tequila, or is it a tier 2 set including the tier 1 sets of scotch, Irish whiskey, bourbon, and blended whiskeys? If we place whiskey on tier 2, tier 1 suddenly becomes full of some related sets (bourbon, scotch, blended whisky, Irish whiskey), and less related ones (rum, vodka, tequila).

It seems intuitive to say that just because a set is more diverse than others does not justify placing it up one tier, and that therefore, whiskey belongs on tier 1, and just happens to have more diversity than other sets in its tier.

However, let us now consider the case of brandy and cognac. These spirits are closely related (in much the same way as, say, bourbon and scotch), yet there isn't a set that describes them both (in the way that scotch and bourbon belong to the set "whiskey"). As such, they are treated as separate sets (presumably on tier 1) despite their similarity. This muddies the entire thought process, here. If brandy and cognac are separate sets on tier 1, then why not scotch, bourbon, blended whiskey and Irish whiskey? Are they allowed to prance around on tier 1 while the various whiskeys get lumped under the same "whiskey" set simply because cognac and brandy do not have their own set they belong to?

I don't really have an answer for this, and perhaps that's because I don't have a vested interest in the specific subject matter. However, the answer could apply more broadly, to other concepts. So if anyone has an answer, please share it.