After the craftsmen at San Francisco’s Anchor Brewing have churned out a batch of their rich, bittersweet, and robust (eight to 10 percent alcohol by volume) Old Foghorn Barleywine Style Ale, one of their most costly products, they make it worth their while.

Taking a cue from frugal brewers of centuries past, Anchor doesn’t let the residual malt mash go to waste. Instead, it sparges (a fancy brewer’s word for " sprinkles warm water over " ) the mash again to make a second brew that’s lighter and less potent (3.3 percent ABV). It’s called, logically enough, a small beer.

But its flavor isn’t small at all. In fact, a wan copper color and puny potency belie a startlingly robust, buoyantly bitter presence. After a pleasantly pungent start, this slightly watery beer mellows into a dry, hop-heavy finish.

Stuff like this has been quaffed, if not always loved, since the time of Will Shakespeare. Slithery Iago himself spoke sneeringly in Othello of " suckl[ing] fools, and chronicl[ing] small beer. " In King Henry IV, Part II, Shakespeare wrote dismissively of " the poor creature, small beer. " In King Henry VI, Part II, a character thundered, " I will make it a felony to drink small beer. "

Clearly, the Bard liked his brews brawny. And his derisive references helped codify " small beer " as a shorthand for anything that’s trivial or unimportant.

We disagree. Sure, it’s hardly high-test. But the complex and coruscating flavors Anchor imparts to this small beer bring to mind the words of Shakespeare’s contemporary Ben Jonson: " In small proportions we just beauties see, and in short measures life may perfect be. "

Anchor Small Beer is available for $3.20 for 22 ounces at Downtown Wine & Spirits, 225 Elm Street, in Somerville. Call (617) 625-7777.