YOU HEAR IT at every beer festival - an excited buzz that flashes through the crowd like lightning: Did you try _____ beer, yet? You've gotta taste it!

It might be a super-funky sour beer, or an extraordinarily hoppy IPA. It's always the Next Great Beer.

Twenty years ago this month, the buzz that lit up the crowd at the inaugural Philadelphia Craft Brew Festival was bigger than just the Next Great Beer. It surrounded Booth No. 406 at the old Philadelphia Civic Center, where two guys with a pair of half-kegs were pouring 2-ounce samples.

By the time they kicked the kegs, the buzz not only propelled the pair's garage brewery into a legitimate business, it signaled the rebirth of the city's entire beer scene.

That beer was Yards Extra Special Ale - ESA for short.

It was April 30, 1995, and more than 5,000 people descended on the Philadelphia Civic Center, in West Philly.

The festival was the brainchild of George Polgar and Mark Saunders, of the old KatManDu Club (now Cavanaugh's Riverdeck), on Delaware Avenue, and David Cohen, who ran Revival Nightclub (now National Mechanics).

"We weren't really beer guys, but we saw there was a passion for it," Polgar said. "The thing is, nobody had done 5,000 people in one place, drinking beer. It was a frightening prospect."

Judging by the breweries that attended, the city was already seeing the beginnings of a decent beer scene. Tun Tavern, Stoudt's, Red Bell and Dock Street were all on hand. So were Independence, New Amsterdam, Arrowhead, Celis and Rhino Chasers - all well-known brands that are now gone.

No one knew about Yards. The brewery, on a short, tight block of Krams Avenue in Manayunk, had gotten its license just three weeks earlier.

"It was our first batch," said Yards founder and president Tom Kehoe. He and his former business partner, Jon Bovit, had decided that an English bitter would be their flagship brand because "it was a style we liked. We took a basic English ale recipe and beefed it up with more chocolate malt and more alcohol to make it a little more ballsy."

The beer was unfiltered, and the pair had stuffed a bunch of dry hops into the kegs to enhance its aroma.

They borrowed a draft-beer dispensing box from a bar in West Philly where Kehoe had worked as a bouncer.

"We weren't sure if it would work," Kehoe said. "We were mostly worried that the hops would clog up the draft lines."

The beer was cloudy, with a raw but full flavor.

Jim Anderson, a former bartender and beer entrepreneur who had recently launched Beer Philadelphia magazine, remembered getting one of the early tastes.

"I was astounded by the perfection of its blemishes," he recalled in an email. "It was murky, musty, malty and deliciously bitter with a soft carbonation."

The buzz spreads

During a Q&A session with two other brewers, audience members peppered Kehoe with questions about the ale. Bar owners visited the Yards booth and put in orders for immediate delivery.

"We sold out all of our entire inventory in that one day, we had so many accounts lined up," Kehoe said.

ESA drew much of its character from its cask-conditioning, in which the ale is re-fermented after kegging. It's a labor-intensive step that was unheard of in Philly at the time.

Likewise, the locals quickly learned that the ale tasted best when served from a beer engine, a hand pump that bypasses the need for CO2 to dispense the beer.

For the first time in anyone's memory, the city was getting a taste of authentic, old-style English ale, served in smooth pours at cellar temperature. Months and even years after the festival, people talked about their first taste of the beer.

Looking back, it seems like a turning point, when Philadelphia had a beer it hadn't borrowed from the West Coast or New England.

"Not only did Yards ESA signal a new era of Philadelphia brewing," Anderson said, "but it was also a welcome break from the ubiquitous amber ale that was killing the East Coast beer revolution nearly as soon as it started."

Yards Brewing grew and moved out of Krams Avenue. It now makes more beer in a single batch than it did in an entire month in Manayunk. Its ESA still thrives, but it's far from a flagship brand. Tastes change; beer drinkers seem to be looking for something edgier.

But Extra Special Ale is still special and, 20 years later, worthy of the buzz.

"Joe Sixpack" is written by Don Russell. For more on the beer scene, sign up for his weekly email update at joesixpack.net. Email: joesixpack@phillynews.com.