Making Wine from Cold-Hardy Grapes

Minnesota's Cold Climate Conference reflects growth of one of the world's newest wine regions

by Bill Ward
wine grape cool cold climate conference minnesota
A crowd of wine professionals gather to hear Steve Johnson, owner of Wisconsin-based Parallel 44 and Door 44 wineries, give the keynote address during the Cold Climate Conference in Bloomington, Minn.
Bloomington, Minn.—Growing cold-hardy grapes and making wine from them might be the ultimate lifelong learning process, if the sessions at the Cold Climate Conference held Feb. 16-18 in Bloomington are any indication. But thanks to the work of researchers and educators, many of whom drew standing-room-only audiences for their presentations at the conference, the learning curve has gotten a little less steep.

The good news: Between the Northern Grapes Project (NGP) and other research at the University of Minnesota, Cornell University and Iowa State University in particular, new knowledge abounds on topics ranging from spraying and trellising to mouthfeel and marketing.

The better news: New grapes such as Itasca and Petite Pearl showed beautifully in seminars, eliciting strong buzz from those who tasted them.

The best news: There was a palpable energy and collaboration during and between sessions, with lively discussions among the 500-plus growers and winemakers in attendance.

“I’ve never seen this group so engaged,” said conference director Steve Unverzagt. It helps immensely, he added, that for the sponsoring Minnesota Grape Growers Association, “the Northern Grapes Project’s mission is totally in sync with our mission, so we have everything finally aligned.”

The director of that project, Tim Martinson, passed along some conclusions from the four-year study that wrapped up last summer:

• There has been a major shift from vertical-shoot positioning (VSP) to high training systems, with high cordon rising from 34% of the vineyards surveyed in 2012 to 50% in 2016. Part of the reason, he added, is that VSP gets half the yield of high cordon.

• Growers are spraying more often, with some using fungicides every seven to 10 days and insecticides from five to 11 times per season. Disease and insect management is “a continuing challenge,” Martinson said, “and something that gets missed is early season treatment.”

• Wine’s economic impact in the states studied rose from $401 million in 2012 to $539 million in 2016, and tourism income more than doubled. Another big increase came in labor income, as vineyards and wineries relied less on volunteer work by family and friends and increased the amount of hired labor. Martinson noted that one grower said in a survey, “Growing grapes is a lot more work than I thought.”

• Northern grapegrowers share several traits, he said: “They’re enthusiastic, they’re mostly part-timers, and they still are developing skills. They’re receptive to technical information but also receptive to folklore and hearsay.…Growing grapes is a knowledge-intensive enterprise.”

• Cold-hardy grapes’ natural acidity remains a challenge. “The bad news is that if you want to get rid of malic acid and keep the tartaric in these grapes,” he said, “It just doesn’t happen.” He also lamented the hybrid grapes’ tendency to bind tannins to proteins.

That vexing dilemma was the topic of an entire talk by Cornell’s Mark Skoglund, who started by noting that the pulp of cold-hardy grapes generally contains more protein that vinifera grapes, and that “the tannins love to bind with the protein.” His research involved a three-pronged plan of attack: 1. Act immediately; 2. Isolate the protein; 3. Treat it.

“The most promising treatment,” Skoglund said, was using a “(protein-fining) bentonite slurry, which got the proteins to a level we can work with.” He noted that in a trial last year, these steps produced the desired results: crush and press, set aside the skins, add a maceration enzyme to the juice, wait a day, rack, add bentonite, rack again, recombine with the skins and then ferment.

Ranging far and wide
The conference covered a plethora of topics, with separate sessions on enology, viticulture and business. Among the more topical subjects:

After a study seeking to discern the best yields and quality for cold-climate hybrids, Carl Rosen touted sandy loam and silt loam but added that “these grapes can tolerate a wide range of physical and chemical properties in soils.” The University of Minnesota soil scientist strongly recommended testing every four or five years for these soil traits: physical (texture and structure), chemical (nutrients, pH) and biological (microbes). Martinson mentioned in his NGP talk that the only cold-hardy grape that seems sensitive to sulfur in the soil is St. Croix.

Safety first, last and always was the overriding theme of Dean Herzfeld’s presentation. The University of Minnesota educational program manager stressed that “it’s all about exposure, not toxicity.…Low toxicity but long exposure is as dangerous as high toxicity in shorter exposure. We should treat all pesticides with the same level of care as the most toxic ones.” The University of Minnesota plant pathology professor stressed the importance of proper pesticide applicators (which “have more control over exposure than toxicity”) and unlined, waterproof gloves at least 14 millimeters thick and 12 inches long. Fortuitously, he added, every country in the world has adapted the same safety language. “We’re globally harmonized. If you’re from the ’60s that’s a really cool thing,” Herzfeld said with a chuckle.

Yeasts: Nichola Hall from Scott Laboratories covered a lot of ground but brought home a predominant message: “Yeast needs your help to drive certain characteristics (in wines). Yeasts are amazing, but they are not infallible. Microbes can and will drive style, but you need a style to drive toward.”

Oxygen et al.:
Drew Horton urged his audience to add sulfur dioxide during cold-settling, to have three inert gases (CO2, nitrogen and argon) as well as a two-stage gas regulator on hand during fermentation and beyond, and to ignore the “myths about sulfites” and use sulfur dioxide as needed. “A dollar’s worth of sulfur can save $100,000 worth of wine,” he said. Most of all, the University of Minnesota enologist added, “Go toward your maturation process with intent. You need to have an intimate relationship (with what’s in the tank or barrel).”

Oak: Chris Granstrom, owner/winemaker at Lincoln Peak winery in Vermont, revealed one secret to his Marquette, which has earned several best-of-show awards: ”I’m not sure the right amount of oak for Marquette is zero, but it’s pretty close to zero.”

Enhancing mouthfeel: In what she admitted was “a really confusing area from a winemaking point of view,” Cornell enologist Anna Katharine Mansfield addressed what can be done in the winery: choosing the right yeast strains and extending sur lees time; using pectoylic enzymes (which “release polysaccharides and change tannin extraction”); malolactic fermentation (“which changes the volatile character and fools us into thinking there’s fuller mouthfeel”), and a late-as-possible addition of tannin powders (“condensed, not hydrolysable”).

Working together
Making the best-possible wine is essential, moderators agreed. The ways that is happening were borne out in “Wine Diamonds,” a lovely, detailed documentary screened three times at the conference (and available at winediamondsfilm.com).

But along with the ongoing advances in growing and making wine, there needs to be more collaboration and stronger marketing, keynote speaker Steve Johnson noted.

“We know that viticulture practices will keep improving, that winery practice will keep improving,” said Johnson, owner/winemaker at the hugely successful Parallel 44 and Door 44 wineries in Wisconsin. “Now is the time to prove to the world that we have quality wines, to set aside Midwestern humility. Let’s find ways to organize and achieve a dream, to express the region’s style and quality. We need to acknowledge how far we’ve come.

“Instead of saying, ‘this wine is like a Cabernet or a Chardonnay,’ we should be saying ‘this is world-class, food-friendly, locally-grown wine.’”

Self-promotion doesn’t come naturally to Upper Midwesterners or New Englanders, Johnson admitted. “We tend to be doers, not actors,” but that can change with the right message.

“People don’t buy what you do, they don’t buy how you do it, they buy why you do it,” he said. “What winery visitors are looking for is expression. You want them to see your passion, feel your passion, taste your passion. They have to feel like it’s authentic, it’s original, it’s inspired. You want them to leave saying ‘these wines mean something to me.’”

That enthusiasm was evident at the Winter Wine Fest the final night, where 30 wineries poured their wines for a sellout crowd. Attendance at this tasting the past four years has risen from 50 to 150 to 450 to 1,100—an indication that the public might just share the attendees’ enthusiasm for what’s happening in the cold-climate wine world.

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