People want what they can't have. In few places is that more evident than craft-beer circles. Scarcity, it would seem, is a virtue, as limited brews induce the most salivation among enthusiasts.

Mark Opdahl and Juno Choi hope to give beer junkies their obscure-ale fix with Saturday's Northern Lights Rare Beer Fest at Minnesota History Center. The duo behind other beery events, including the St. Paul Summer Beer Fest and the Mankato Craft Beer Expo, are bringing together 30 specialty-keg-toting breweries for a tasting party littered with vintage, one-off or otherwise hard-to-come-by beers.

"This is a super high-end version of what we really do — try to give the attendee the full experience," Opdahl said, bellied up at Stout's Pub in Falcon Heights. "We want to offer them beers that they're never going to be able to try otherwise."

Specialty brews garner the longest lines at beer festivals, and Opdahl's isn't the first attempt at curating a limited-only fest. Though it's tough to match their infamously star-studded lineups, Northern Lights is modeled after events like the Denver Rare Beer Tasting, which coincides with the Great American Beer Festival, and the Firestone Walker Invitational Beer Fest in California. Like the Denver bash, Northern Lights has partnered with Pints for Prostates, donating proceeds from a silent auction and a portion of ticket sales to the cancer-fighting charity.

The craft-beer era has ushered in a wine-like appreciation for vintage ales, and beer collectors (Opdahl included) are stashing bottles to crack years after they were brewed. "There was a point where I had over $10,000 of beer in my cellar," the 31-year-old said.

Breweries, too, are setting aside coveted kegs. A handful of them have dipped into their cache for Northern Lights. For Saturday's sampling fête, local heavyweight Surly Brewing Co. is breaking out 2010 and 2011 versions of its lusted-after Russian imperial stout, Darkness. "I was kind of shocked to hear that [president] Omar [Ansari] approved that for this fest," said Surly brewmaster Todd Haug. "There's never enough of it."

Not all beers age well, Haug said, noting that Belgians, sours, stouts and barleywines with high alcohol content tend to cellar better. Over time the beer oxidizes, altering the beer's flavor profile. With Darkness, the intense hop character softens, and the malt components develop. "You get a lot more of the cherry and raisin — almost like aged-wine characters, like a port or sherry — those dried fruit flavors coming out," he said.

With 70-plus aged, short-run or cask-conditioned brews at Northern Lights, how to choose? As with any beer fest, strategic sampling is in order. These eye-catchers belong on any suds head's radar.

Lagunitas Brewing Co. — 2008 Olde Gnarlywine: This semi-retired precursor to the NoCal brewery's acclaimed Brown Shugga' is the eldest at the festival. Compare the 2008 version to 2011's run (also on hand).

Fitger's Brewhouse — Starfire Reserve Pale Ale: The indomitable Duluth brewery is bringing its souped-up imperial version of its Starfire pale ale — a Minnesota classic on steroids.

Grand Teton Brewing Co. — Huckleberry Sour: Sour freaks should heed this imperial witbier, aged for three years in chardonnay barrels with wild yeast and 65 pounds of huckleberries — the only keg to make it to Minnie, Opdahl boasts.

Boulevard Brewing Co. — Foeder Projekt #1: Sort of a happy accident, this sour ale initially was slated as a blend beer. But after spending six months in a foeder — a big ol' wooden barrel normally used in winemaking — the Kansas City beermaker deemed it fit for release (with limited availability).

7-10 p.m., Sat., 21-plus, $100 ($20 designated-driver tickets), Minnesota History Center, 345 W. Kellogg Blvd., St. Paul, www.northernlightsrarebeerfest.com

Beer gala for good cause

Northern Lights isn't the only beer bash in town this weekend. The first-ever Brewer's Ball hits the DQ Club Room at TCF Bank Stadium on Friday night, featuring 20 mostly Minnesotan breweries. It's hard to hate on boozing for charity, and this beer gala, hosted by Chris Reuvers of ESPN 1500's "The Beer Show," doubles as a fundraiser for the Cystic Fibrosis Foundation. Participating breweries include Brau Brothers, Surly, Fulton and more.

7-11 p.m., Fri., $95 ($150 VIP, includes 6-7 p.m. reception), TCF Bank Stadium, 2009 University Av. SE., Mpls., www.mnbrewersball.com

Party-free party bar

Shots are no longer being poured at one downtown Minneapolis party spot. At least temporarily. The windows of Uncle Buck's "kick ass party bar" have been covered for weeks, and its website indicates that the bar is closed for remodeling. No word on whether its "strategically placed stripper poles" will remain, as messages left at the Warehouse District bar were not returned by press time. The space on the corner of 5th Street and 1st Avenue N. has seen its share of makeovers, since the former Drink re-emerged as the short-lived Wellman's Pub in 2012, before rebranding again to Uncle Buck's later that year.

Michael Rietmulder writes about bars, beer and nightlife.