On March 11 and 12, BeerAdvocate.com welcomed brewers from across the country to its Extreme Beer Fest in Boston. As defined by the website, an extreme beer is "a beer that pushes the boundaries of brewing through creativity and innovation." Beers for this festival offer different ingredients and techniques than the typical ones.Because of the goals of this event, it is no surprise that the Dogfish Head Brewery sponsors this annual event. According to its website, Dogfish Head is known for its "off-centered ales [made] for off-centered people." They make beers infused with fruit and spices and use ancient brewing techniques. The event was divided into 2 days with two different lineups of beers. Friday night was the exclusive Night of the Barrels featuring rare barrel-aged beer.

Saturday brought two regular sessions featuring experimental one-off beers that challenged notions of what typical beer tastes like.

Night of the Barrels offered barrel-aged beer. A new American staple, many brewers will age beer in different types of barrels to get different flavors. I have talked about this style before.

Many of the top-rated beers in the country are aged in some form of wooden barrel, and often the barrels have previously been used to age other alcohol. This imparts woody flavors and allows for other alcohol notes to come through.

One highlight of Night of the Barrels was a keg of Samuel Adams Utopias. This highly experimental, extremely rare and very expensive beer delivered a delicious blend of port wine, honey and a bit of bourbon.

Utopias is 29-percent alcohol by volume and one of the highest alcohol beers in the world. Sam Adams also brought to the festival the aptly named WTF-the company wouldn't even give a description of what it was or its alcohol content. The beer was disgusting; it tasted of a mix of pine needles and cough syrup.

Also at Night of the Barrels was the Bruery's Black Tuesday. This is an insanely rare imperial stout that sports 15-percent alcohol. Despite the hype, the beer was overwhelming with a lot of bourbon and a lot of booze; a decent beer but worse than expected.

The real winner for me was California's Lost Abbey and its Double Framboise de Amarosa. This beer had a sour raspberry flavor with a very sweet taste that finished tart. The balance of the two was sublime. Lost Abbey Double Red Poppy, a Flemish red ale, was also a nice sour brew.

The Saturday session delivered an interesting challenge to brewers. BeerAdvocate owners, brothers Todd and Jason Alstrom, asked that all brewers make an "extreme session beer" for the festival.

When most aficionados think of the term "extreme" in the field of beer, they instantly assume that this must be an alcohol bomb that knocks one out in flavor and amount of booze. BeerAdvocate wanted to challenge that notion and asked that brewers reinvent their brews with beers that were less than 5 percent in alcohol.

To accomplish this, the brothers got together with the brewers from Dogfish Head and made Fungus Tea'Mungus, a 4.1-percent beer brewed with both yeast and Kombucha, a fermentable tea. The beer offered a light flavoring of tea, citrus and a bit of a sour pucker from the bacterial Kombucha cultures.

Haverhill Brewery brought sour wheat-smoked ale at 3.2 percent. The wheat crop was smoked over an open fire in a technique similar to the German Rauchbier. It was then fermented with wild yeast and bacteria.

It offered an intense bacon flavor with a bit of sour pucker at the end. The flavors were very over-the-top, and it was not my favorite beer. However, it was definitely extreme.

One of the most interesting beers was Sierra Nevada's Saison de Haricot. This was a lighter beer fermented with cherry Jelly Belly jelly beans. The idea was fascinating to me, as cherry jelly beans are one of my favorite candies.

Unfortunately, the idea didn't translate well. The cherry was hardly noticeable, and something simply tasted off about the brew.

The real winner of EBF was Stone, which brought all session beers. Their Self Conscious ale was a Black Indian Pale Ale, which offered the hop profile of a double Indian Pale Ale but had a 4-percent alcohol content.

The beer was earthy, citrusy and herbal in the finish and tasted delicious. Stone proved that beers with little alcohol could still have big flavor.

EBF is one of the most important events of the American beer calendar. Some have called it the Super Bowl of beer fests and, in my opinion, the offerings lived up to that designation. This was a fantastic event at which to try experimental beers, and I highly recommend attending next year.