Rolling around town in a little yellow school bus, listening to a historian spout factoids about the founding of the Brewery Blocks (in 1856 by Henry Weinhard) seems a sobering experience. The intrepid handful of beer hounds gaze out the windows as the old charter clatters over the Fremont Bridge (America's longest tied-arch bridge).

We are thirsty, and not just for knowledge. Luckily, beer can be the best teaching aid.

About once a month, tour leader Jim Long gathers thirsty troops and sets off on the Brew Bus tour. For the past nine years, the local author and historian has led five-hour junkets to breweries on the bus he says is his "College of Brew Knowledge."

This month's tour is made up of an intimate brood of seven people, and our trip delivers a high-quality beer buzz without the puke-in-the-gutter pub-crawl mentality.

"Do we need a slop bucket?" one woman asks as the server brings a sixth pitcher of Portland Brewing suds to the table at the Northwest Portland ale house. "Where I come from that's called beer abuse," a second tour member chimes in.

Back on the bus, after an hour of oversized "tastings," Long launches into a dissertation on yeast and hops, beer's building blocks. "Beer only has three enemies," he lectures as the bus charges toward Northeast Portland and Widmer Brothers Brewing Company. "Air, heat and Mormons." A stout guy in the front bench seat can't stop laughing.

But it's in the tasting room at Widmer's that our real history lesson begins: Volunteer guide Robert Luehrs lets us in on the secret that Jesus might have turned water into beer, not wine. (The Aramaic word used to describe Jesus' magic trick in the Good Book translates to "strong drink," not vino, he claims.)

When Luehrs hands out some hops, one of beer's main flavor agents, a pale, delicate woman grabs a handful of the fragrant pods and inhales deeply. Luehrs mentions that hops are related to cannabis.

Our bus catches air on a giant freeway pothole en route to Southwest Portland's Tuck's Brewery. By now, Long and his fastidious school-book lecture style are both trashed as he leads us in a singalong of "Don't Worry, Be Hoppy."

We need another drink before reality catches up with us. Tuck's brewmaster Max Tieger pours frothy tasters of his smooth Oatmeal Cream Stout. Striding through the door, here comes Luehrs, who has decided to catch the tour's last stop. A collective boozy cheer is raised.

As the Brew Bus rolls back to town, we realize that the tour's real lesson lies in introducing locals to Portland's slightly sodden brewers' community. That's worth another round, isn't it?