Terroir is a term that most drinkers would associate with wine.

It refers to the unique flavors brought about by the climatic and soil conditions where grapes are grown and the expression of those flavors in a finished wine. But can the term also apply to beer? An up-and-coming Minnesota hop industry is aiming to find out. Like grapes, the character of hops is highly subject to the place where they are grown. The amount of bittering acids and the types of oils responsible for the fruity, spicy and herbal flavors that IPA lovers adore differ from region to region and even field to field. German hop growers say that the same variety of hops grown in one field is different from those grown across the street.

So do Minnesota-grown hops have a particular terroir? Eric Sannerud, CEO of Mighty Axe Hops in Foley, Minn., thinks they do. At 80 acres, Mighty Axe is the largest grower in the state.

"What I have experienced in the beers that our hops have gone into is that there is a more prevalent orange flavor across the board," he says. "Strictly looking at analysis of oil content, they tend to be much higher in myrcene [the aroma] than West Coast hops. Myrcene is a component that can create hoppiness, pineyness, grassiness."

But not all varieties are the same. Some have more pineapple character than their West Coast counterparts. "There is not going to be one rule across the board. Each hop is going to interact with terroir in a different way because it has a different set of genetics and a different way of expressing itself."

There are currently around 60 commercial hop growers in Minnesota, according to John Brach, president of the Minnesota Hop Growers Association (MHGA) and grower at Stone Hill Farm in Stillwater. Together they have an estimated 120 acres in production.

Minnesota hop growers face many unique challenges. "One of the largest challenges that growers face is selecting the proper varieties that perform well in our climatically distinct region," says Joshua Havill, MHGA vice president. The growing season is short. Minnesota's fertile but heavy soil retains water, a problem exacerbated by higher rainfall totals relative to other hop-growing regions. Hops don't like wet feet.

"Another issue is that we cannot grow the sexy proprietary varieties that brewers want," Brach said. Some hop varieties are developed publicly by the U.S. Department of Agriculture. These can be grown by anyone free of charge.

But many of the hops that are currently in high demand by brewers and consumers were bred privately. They cannot be grown without paying a hefty licensing fee, driving up costs to both grower and brewer. Additionally, some of these varieties don't grow well in Minnesota's climate.

In Waseca, Minn., Charlie Rohwer, a scientist at the Southern Research and Outreach Center of the University of Minnesota, is working to resolve this issue. Rohwer started growing and researching hops in 2010. Working in collaboration with brewers, he is trying to develop hop varieties that are both agronomically suited to Minnesota and possess the flavor and aromatic qualities that brewers and consumers desire. In his words, he's seeking the "Honeycrisp [popular apple, newly developed] of hops."

The timeline for developing a new hop variety is a long one. Crosses made by Rohwer in 2012 are only now being tested by brewers. They are still a few years from commercial release — if they are released at all.

It takes a lot of plants to find the one that works. A lot of considerations go into selecting the ones to continue growing, starting with agronomic viability, i.e., will they grow here?

"You're looking for a diamond in the rough." says Rohwer. "There are a whole bunch of plants and you have to narrow it down. You're basically killing the ones that don't grow well. You rub them a little bit and the ones that don't really smell very good, you get rid of those. And finally you narrow it down to one that you're like, 'Hey, this one seems all right.' "

That one plant is sent on to growers to expand production and confirm viability. The hops then go to a small number of brewers to establish desirability. Test beers are brewed and evaluated. Feedback is gathered from consumers. Those deemed favorable are given to an expanded list of brewers for further experimentation. If a demand can be established, the hop may finally be named and put into commercial production.

Minnesota's craft brewers are gradually warming to Minnesota-grown hops, though limited production means limited availability to brewers. Many beers that prominently feature Minnesota hops are small-batch brews available only in the brewery taproom or in extremely limited package release. Some brewers, though, have adopted local hops more broadly.

"We use Minnesota hops in every beer we brew," says Derek Allmendinger, head brewer at Unmapped Brewing in Minnetonka. "I bitter every beer with hops from multiple farms around the state. We also do a Minnesota Hop Series of pale ales made exclusively with Minnesota and some extremely-western-Wisconsin-grown hops. We try to do one series beer a quarter and have one coming out soon, made with Mighty Axe Artic hops." It will be released in the taproom during the third week of January.

With high-quality hops available in abundance from other regions, often at lower prices, why would brewers opt for locally grown hops?

"Many reasons." explains Allmendinger. "In a highly competitive market, where differentiation can mean sales, adding Minnesota hops to our arsenal gives us more flexibility, creativity and a way to offer something to our customers that they likely can't find anywhere else."