New Belgium Brewing Company has debuted the 2017 edition of its original sour beer, La Folie, celebrating 20 years of brewing sour beer this month.

The brewery first launched its wood beer program in 1997 with La Folie, its interpretation of a Flanders-style sour brown ale.

The sour beer craze that has swept the craft beer industry in the past few years can be partially attributed to the introduction of La Folie, said Shannon Arledge, a liquid center representative at New Belgium.

“La Folie is heralded as the beer that started it all,” Arledge said.

According to Arledge, though the style has been produced in Europe since the 1300s, it has only had a real presence in America for about 25 years. Now, the style is booming.

“In the past five years, America’s drinking of sour beer has skyrocketed,” Arledge said.

Morgan Bergine, also a liquid center representative, said she thinks the reason for La Folie’s popularity stems from its broad appeal.

“Beer geeks might drink it because they like its complexity,” Bergine said.

Since the introduction of La Folie, the brewery’s blending team has continually refined its methods of tasting, analyzing and blending the beer.

Every year, Eric Salazar, New Belgium’s Wood Cellar Manager, and Lauren Salazar, New Belgium’s Sour Beer Blender, coordinate a blending of beer from various oak barrels called foeders.

“We’ve been blending and experimenting with sour wood beers for two decades and as the name La Folie implies it’s always with a touch of eccentric madness,” said New Belgium Spokesman Bryan Simpson.

La Folie, French for “the folly,” is synonymous with lack of good sense or foolishness.

The aging process begins by adding New Belgium’s brown lager called Oscar into massive French oak foeders previously used in winemaking. The beer ages for one to three years before use.

On a monthly basis, a panel of validated tasting experts taste the various foeders and make note of flavors and other changes in the beer. The sours are also scientifically analyzed in a lab on-site.

“Lauren (Salazer) has notebooks from like 20 years ago with notes about the beer,” Arledge said.

Barrels are handpicked for blending of the various aged beers by Lauren Salazar based upon the tasting notes and an idea of how the beer has traditionally tasted in the past.

“We combine multiple barrels based on continual tasting to create a combination that is just right,” Simpson said.

But the barrels are never fully depleted, according to Arledge. The two original oak barrels have contained some of the same Oscar that was first added in 1997, giving the blenders a rich palette of flavors with which to mix beers.

Today, New Belgium has a forest of 65 foeders that vary in size and shape. The size and surface area within them determines how long it will take for the beer to acidify, Arledge said.

According to the brewery’s website, the 2017 La Folie is a sharp, tart sour ale full of green apple, deep cherry, dark chocolate and tannin-like plum skin notes. The beer is 7 percent alcohol by volume and is only available in 22-ounce bombers and on draft.

As for pairings, Arledge suggests a baked rich brie, topped with cherry chutney and served with crispy crostini. According to Bergine, La Folie plays well with any red meat or charcuterie.

For more information on the history of New Belgium’s sour beer program, visit newbelgium.com.