IPA. These three letters capture the spirit of craft beer, with all its energy and craziness and adventurous enthusiasm. IPAs kicked off this brewing revolution we're living through together. And IPA remains craft beer's restless crucible, the beer style in which we see the most innovation. So it's strange how these three letters that stood for so much have come to mean so little.

Over the past year I have drunk many beers that were sold as IPAs. I'm sure you have, too. And in this time I've seen the term slapped onto cans containing some very different beers. In fact, these differences seem wider now than ever before.

I've had sour IPAs, fruity IPAs, bitter IPAs, and brut IPAs. I've had IPAs with ABVs ranging from somewhere north of 10% all the way down to less than 3%. I've had IPAs that were clear and IPAs that were cloudy. I've drunk New England IPAs so turbid they looked like orange juice. I've had bright red fruited IPAs, white IPAs, and black IPAs.

Bob Pease, CEO and President of the Brewers Association, agrees. "IPA is less of a single style now and more a platform for innovation," he says. His list of variants gets even wilder than mine. It includes imperial, West Coast, Belgian-style, Brett, or wild IPAs, plus spiced, herb, or vegetable IPAs.

Vegetable IPAs! How did it come to this?

Think back to the 1990s, when a new breed of hop-forward pale ales shook up the nation's drinking culture. These beers started to coalesce around the label “India Pale Ale.” At the same time, craft brewers were producing dark hoppy beers and calling them all sorts of things: New World porter, Cascadian dark ale, India black ale, American dark ale. Nothing quite seemed to stick.

Then someone somewhere dreamt up the oxymoron “black IPA.” It's not clear why this name endured above all others. Probably people felt these beers had more in common with modern IPAs than with traditional, roasty porters. Either way, its success loosed the term IPA from its moorings. The name no longer connected back to the ur-IPA, conceived in London and birthed in Burton. Instead it referred to something more nebulous, a shared hop-forward nature.