State of hoppiness: How many IBUs in your IPA?

The American palate demands more excitement than it used to. Millennials, in particular, are open to experimenting. The spicier the better. Sriracha. Wasabi. IPAs with 100 IBUs.

IB ... what? IBU stands for International Bitterness Units, a measure of the bitterness in beer. A Budweiser, for example, might have 12 IBUs, while a Stone IPA might have 77. That's what you would call a very "hoppy" beer, since much of the bitterness comes from the aroma hop flowers used in flavoring craft brews.

Harriet Taylor | CNBC

Bridgeport Brewing was established in 1984, IPAs Bridgeport Brewing gets ready for July 4th party.

High IBU levels have become very popular as home brewing has grown from the garage to a thriving commercial industry. Last year, the Brewers Association said overall beer sales fell nearly 2 percent, while craft beer sales grew 17 percent.

Read MoreHop prices soar as US craft beer boom takes off

The king of craft beers is the IPA, which requires a lot of hops. "People expect you to make an outstanding IPA," said Jeff Edgerton, the brew master for Bridgeport Brewing Co., the oldest brewery in Oregon.

The Pacific Northwest is where most of the hops used in IPAs are grown, and Edgerton said demand is outstripping supply. "Pricing is crazy," he said. "Five years ago probably half the people bought hops on the spot (market). Nowadays I bet probably 80 percent of the breweries are buying them on contract."

Harriet Taylor | CNBC

Jeff Edgerton, Brew Master for Bridgeport Brewing says the people that sell hops, they're driving the bus right now.

There are concerns that as some IPAs have topped 100 IBUs, they're too hoppy for human taste buds to know the difference. "Hops are a quick way for beginning brewers to disguise flaws in their beer," warned beer writer Adrienne So in Slate last year.

Even here in the heart of hops country, some acknowledge that less-gifted brewers could damage craft beer's reputation. "There's a chance we could go too far," said Edgerton, while admitting, "I love hops." However, he says it's important to balance the bitterness with flavors. "You have to be very creative."

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So what does a hoppy Bridgeport beer taste like? In the video clip, Edgerton lets one reporter have a sip, and explains why a beer with 75 IBUs doesn't have to leave you feeling bitter.

—By CNBC's Jane Wells