The name "imperial" originally came from the Thrale's brewery in 18th century London, which brewed "Russian imperial stout" or "imperial Russian stout" for export to, you guessed it, Russia, then ruled by Catherine the Great. The style had more or less died out, but was resurrected by North Coast Brewing in Ft. Bragg with their Old Rasputin.
As it turned out, two of the beers that The Jug Shop had in their Kiwi tasting were imperial stouts, and as it happened, at out most recent tabletop RPG session, my friend Andrew, who knows my fondness for the style, brought both of them, as well as 3 other varieties, so I can give you a truly imperial review.
Note: You may notice is that the IBU for these beers (when I could find them) are rather high. These beers tend to have a lot of residual sweetness, so they require a lot of bittering to balance them out. Generally, however, most of their flavor profile comes from the grain, not the hops.
Moa Imperial Stout
My least favorite of the bunch, although it again started at a disadvantage by being in the damned green bottle. It was the least complex of the bunch and a little on the dry side for my taste, although still pretty good.
8 Wired iStout
I really liked this one. The flavor was much more assertive than the Moa, sweet, although maybe a tad on the syrupy side, but it was really delicious. One odd thing about the 8 Wired beers, though, is that they come in pint bottles (16 oz). Just sayin'.
Firestone Walker Parabola
With Parabola, we get into the realm of specialty beers - beers that craft brewers don't brew all the time, or only in limited amounts as "premium" beers. I'm not a big fan of Firestone Walker's "everyday" beers - their I find their Double Barrel pale kinda bland, and their Union Jack is a passable IPA. But they make some good seasonals, like their Velvet Merlin (originally called "Velvet Merkin"); and holy crap, do they make some good limited release beers!Their Double Jack double IPA is excellent, as is their Wookie Jack black rye IPA. The barrel-aged Parabola, first released this year, is an outstanding imperial stout, rich and complex. It comes in a 20-oz bottle, though, and at 13% ABV, be prepared either to share or to surrender the day to the couch.
Fifty/Fifty is a newer brewery and brewpub in Truckee CA, a little mountain town up near Lake Tahoe. But, despite their small size, they're a serious contender for my heart, or at least my stomach, as they have a whole pallet of outstanding beers, among them Eclipse; which, like the Parabola, is aged in barrels, in this case used whiskey barrels, which is a delicious trend among craft beer makers. (I myself fake it for my Zwarte Piet holiday imperial stout, with oak chips and rotgut bourbon.) This adds lucious woody and vanilla notes to an already complex and delicious beer. In fact, I was so busy enjoying it, that I didn't realize that they actually have multiple releases of this beer each year, aged in barrels of different whiskeys. This year there have been 7 in all, including Elijah Craig 12- and 20-year, a rye, and a brandy barrel. I don't know which one we had (the bottle having gone to the great recycling center in the sky), but whichever you try, it's sure to be wonderful.
North Coast Old Rasputin Barrel Aged XIV
Old Rasputin, probably one of (if not the) first commercially-produced imperial stouts in the US beginning nearly 20 years ago, is still one of my favorite beers. They've been selling it aged in bourbon bottles for several years now, and it's one of the first bourbon-barrel aged beers I ever had. Like its bretheren, this is a wonderful treat, although in comparison (having had the Parabola, Eclipse, and Old Rasputin on the same day), I actually like the younger upstarts better. The OR was just a little too dry, and maybe too woody, compared to the richer flavors of the other two. Of course, I also like really intense flavors - coffee that can peel paint, food spicy enough to make me sweat, IPAs that I can feel eroding the enamel on my teeth - so you might find this one a little more balanced.
Moa Imperial Stout. 10.2% ABV, IBU ?
8 Wired iStout. 10% ABV. 70 IBU.
Firestone Walker Parabola 3. 13% ABV, IBU 60.
Fifty/Fifty Eclipse. 9.5% ABV. IBU ?
North Coast Old Rasputin Barrel Aged XIV. 11.2% ABV. IBU ?