I suppose we should get this out of the way first: I am not comfortable with the allusion by Ninkasi's Sleigh'r to the thrash metal band Slayer. Afficianados of heavy metal will assure you that Slayer is full of more thrashy goodness than the competition (Metallica partisans notwithstanding). I am not an afficianado. (I'm more of a Ponytail, Eels, Tom Waits, Miles Davis kind of man.)
But I can forgive Ninkasi their musical tastes. Beer, they say, unites all. Sleigh'r is, unexpectedly, a double alt. Ninkasi, like--well, like a heavy metal band--tends to stick to a narrow range of beers. The Ninkasi standard is an ale, large, loud, and muscular. They have dabbled in variants before--Schwag, for example. Sleigh'r is in this mode, a fun one-off.
I have to confess, I judged this beer by its label. I didn't expect much, yet it was absolutely gorgeous pouring out. You think it's chestnut brown until you hold it up to the light and see the Christmas cranberry. It produces a lush, rich head and gives off a wonderful malty nose. In the end, it's a pretty straightforward interpretation of style (which also caught me off guard). The malt body is rich and clean, and there are nicely insistent hops. They're not showy or funky, just assertive, as you'd hope for in an alt.
Overall, very nicely done. I'd give this a B+.