Good things come in small batches. Harpoon’s stately new oatmeal stout comes from a very small batch — only 100 barrels, labored over lovingly — and it’s very, very good.

But the fact that there are a mere 100 barrels of this brawny brew in existence is not good at all.

It’s that good.

Concocted up north in the brewery’s Windsor, Vermont, drink tank from a recipe thunk up by VP of Brewing Operations Al Marzi (that’s his scrawled signature on the label, right next to the batch date), this stygian stuff — bracingly bittersweet, with a luscious roasted-malt nose and a pleasingly plangent dry-hop finish — is just the first installment in Harpoon’s 100 Barrel Series, a specialty line designed to give Harpoon brewers a golden moment to strut their stuff with a beer of their choosing. Al Marzi said let there be dark. And he saw that it was good.

There’s just not a whole lot of it around. And 100 barrels of the next beer in the series (a Belgian-style wit) are due to roll out in the not-too-distant future, so get some of this black gold while the getting’s, y’know ... good.

Available for $3.99 for a 20-ounce bottle at local Kappy’s, Martignetti’s, and Blanchard’s stores, and on tap at the Burren and Redbones in Davis Square, Somerville, and other local establishments.