Oskar Blues Deviant Dale’s

This aggressive imperial IPA was born when several mislabeled bags of extra-dark, extra-sweet crystal malt were added to what should’ve been a batch of Dale’s Pale Ale. Rather than dump the liquid, brewers dry hopped the bejesus out of it; the resulting brew won silver at the Great American Beer Festival in 2011.

Fat Head’s Semper FiPA

2015’s hop shortage meant that Mike Hunsaker, brewmaster at Fat Head’s in Portland, Oregon, didn’t have enough Simcoe or Citra to make the brewery’s flagship Head Hunter IPA, so he crafted a recipe with completely different hops. It worked. “Not only did it pull us out of the fire, it’s part of the rotation now,” Hunsaker says.

New Glarus Serendipity

When Mother Nature annihilated most of Wisconsin’s cherry harvest in 2012, brewmaster Dan Carey couldn’t make the brewery’s beloved Wisconsin Belgian Red. Luckily the apple and cranberry crops fared well, so Carey combined them with the cherries he could gather and placed the beer in oak. The cranberry juice cocktail- and mulled apple cider-flavored “happy accident fruit ale” is now a year-round release.

Saint Arnold Boiler Room

In 2014, 2,500 pounds of malt spilled on the ground instead of into the upcoming batch of Fancy Lawnmower. Brewers didn’t give up; when combined with a lambic and left in a hot boiler room to sour (hence the name), the half-strength wort evolved into a lovely little Berliner Weisse.

Port City Derecho Common

On June 29, 2012, Port City’s head brewer, Jonathan Reeves, experienced a “derecho”: a giant windstorm that can cause tornadoes, thunderstorms and flash floods. The storm knocked out power, causing a tank of lager to ferment at much hotter temps, morphing the beer into a California Common. Reeves still brews Derecho Common the same way—intentionally, now—and releases it yearly on the anniversary of the storm.

The Bruery Black Tuesday

The Tuesday morning this 19% imperial stout was made went like this: First, a leaky pump; then, an overflowing mash tun; next, a stuck sparge; and finally, a spill that sent hot liquid and 170-degree water flying all over the brewery. As punishment, brewers condemned the ale to bourbon barrels for more than a year and gave it an appropriate name: Black Tuesday.

Innis & Gunn Original

When Dougal Sharp, then-head brewer at Caledonian Brewery in Edinburgh, Scotland, first brewed this Scottish ale for the whiskey maker William Grant & Sons in 2002, he did so thinking it would only be used to season the distillery’s barrels and then be sent down the drain. Distillery workers, however, loved the beer so much that they would sneak it home in bottles and empty buckets. Sensing he’d inadvertently crafted a winner, Sharp founded Innis & Gunn, which still makes the original oak-aged ale today.

Right Brain Dead Kettle

When the kettle that was warming the first batch of this IPA croaked, nothing could bring it back to life. Russ Springsteen, Right Brain’s owner, had a solution: Extend the beer’s whirlpool and stuff it full of hops while it ferments. The beer’s boiled all the way now, but still gets a fat dry-hop addition. It premiered in cans for the first time in April.

Lagunitas Sucks

Lagunitas’ brown sugarspiked strong ale, Brown Shugga’, takes a long time to make—so long that in 2011, brewers nixed it because they couldn’t spare the fermenter space. As a peace offering, they instead brewed the humbly named Sucks, whose tropical, grassy hop flavors won over fans and became a year-rounder.

He’Brew Funky Jewbelation

The 2008 edition of Jewbelation Ale was a catastrophe: The yeast, expected to finish fermenting after the beer reached 15% ABV, gave up around 11%, leaving the entire batch undrinkably sweet. To save it, brewers blended in a variety of beers they had resting in barrels. A rebreed batch won silver at the 2014 World Beer Cup; the 2016 vintage combines eight He’Brew beers aged in bourbon and rye whiskey casks for a riotous flavor of tart cherries, blackberry jam, coffee beans and oak-aged cola.