Midwest Vintners Evaluate New Varieties

Cold Climate Grape Conference features tastings and sessions on Itasca, Crimson Pearl

by Bill Ward
scandanavia u.s. wine sales
Jenny Thull, who manages the University of Minnesota’s research vineyards with her husband John Thull, holds a cluster of La Crescent grapes in the couple's own vineyard. Developed in 2002, La Crescent was one of several varieties that were the focus of tastings and seminars at the recent Cold Climate Grape Conference.

Bloomington, Minn.—In a nascent industry, the focus is constantly on what’s new and improved. So not surprisingly, seminars on new grapes including Itasca and Crimson Pearl and the latest research on yeast and soil were among the best attended and most buzzed-about presentations at the recent Cold Climate Grape Conference.

Itasca, a white grape released in 2016 by the University of Minnesota (UM), was the topic at two sessions: a tasting of eight iterations and a presentation on growing techniques. The annual conference, held March 15-17 in Bloomington, Minn., also included grape breeder Tom Plocher overseeing a tasting and discussion on Crimson Pearl; Scott Labs’ Katie Cook delving deeply into yeast nutrition; Iowa State University’s Mike White revealing the dirt on soil (including his “Tighty Whitey Test”), and a rousing keynote address by sommelier Doug Frost.

Anticipation for the Itasca discussions was high because commercial vines have been in the ground for only a year or two, although the wines at the tasting came from vines planted during UM’s pre-release research process. “The majority of the known amount of Itasca in the world is in this room,” said a smiling Drew Horton, UM enology specialist.

Eight wines were poured, with two versions each (malolactic fermentation and non-ML) of four different yeast treatments: DV-10 control yeast, Lalvin’s K1, AWR1 Alchemy and Laffort VL1. Horton said the VL1 and Alchemy “went right through ML,” while the other two had problems completing that fermentation. He also noted that the VL1 yeast raised the pH the most, from 3.08 when the grapes were picked to 3.34.

Several of the wines earned multiple votes from attendees as their favorites, and the consensus among winemakers afterward was that they preferred the ML renditions.

John and Jenny Thull, who manage the ten acres of research vineyards for the grape breeding program at UM, discussed growing strategies for Itasca. The couple has worked with a “mother vine” planted in 2004, but their attention for the conference session was on the kind of younger vines found in commercial vineyards. “It’s gonna grow fast like a teenager in those first couple of years,” John Thull said. “It’s not as vigorous as Edelweiss but more than Frontenac Gris, so we want to put more fruit on it and slow its growth. Some vines begged for spur pruning. … Saving two shoots is a good idea the first year. Growth can later be focused into one shoot if progress is too slow.”

Early training is essential, Jenny Thull noted. She is an advocate of vertical shoot positioning (VSP) and said Itasca’s upward shoot growth could pair well with VSP. But the Thulls reported that high cordon training meant “less work and more productive vines.”

According to John Thull, “Young, high-wire trained vines are easier to manage, and the canes generally give larger clusters. The shoot growth is a little chaotic, though.”

He added that “secondary buds tend to push, so they can be removed,” with Jenny quickly adding “very carefully.”

Crimson Pearl also likes a high cordon, Plocher said, “because it droops.” He noted that “it starts hardening off wood pretty early, with hardening done by harvest.”

Plocher said the red grape shows moderate vigor and good disease resistance in the Midwest with a normal spray program (twice pre-bloom, twice post-bloom). The newest grape from the Hugo, Minn.,-based breeder has the same parents as his Petite Pearl but ripens five to seven days earlier. Typical harvest in the Twin Cities, he said, comes in at 22° to 23° Brix, 3.4 pH to 3.8 pH and 0.7% to 0.8% RS. He recommended a 48-hour cold soak followed by 15 to 16 days fermentation on the skins.

He described the wines as “fruity, little lighter style, with true crimson red color and moderate, soft tannins.”

The variety is more affected by yeast strain than its sibling, but “all styles have good balance between acid, tannin and alcohol,” Plocher said.

Feeding the catalyst
As cold-climate grape growing comes of age, so, too, should the approach to the yeast that goes into the juice, said Cook, a veteran winemaker and sales representative for Sonoma-based Scott Laboratories. But the choice of yeast type is not always the most important step. “In a lot of cases it doesn’t matter what yeast you use if you don’t feed it properly,” Cook said, adding that that is particularly true in colder climes. “In California they don’t even talk about nitrogen levels this high.”

She recommended vintners measure Yeast Assimilable Nitrogen (YAN) early and often, even before picking, “because a lot of YANs are in the skins.”

YAN is one of several factors in calculating how much yeast to add — along with sugar, temperature, oxygen and pH — and yeast nutrient requirements include nitrogen, carbon (sugar), minerals, vitamins, oxygen and limpids. Nitrogen is particularly important because it has a significant influence on fermentation rate and cell population, and because yeasts consume organic nitrogen more quickly than ammonia nitrogen.

What’s beneath our feet
As important as yeast might be, nothing in the wine world matters without suitable soil. ISU’s viticulture specialist Mike White pointed out, “in the last 10 years, everything is going toward soil health because that solves a huge amount of problems.”

In his work with the university’s extension program, White said he has assessed many acres of land that farmers might want to convert from two of Iowa’s primary crops, corn and soy, to vineyards. At these sites, he studies only the top 12 inches, “and all my assessments are chemical and physical, not biological. If you have the chemical and physical where you want it, you can work on the biological.”

White cited worm castings as “fantastic fertilizer” and said he has become more open-minded about biodynamic practices, which he “used to think was weird as hell, and it still is, but about 60% of it makes sense.”

Speaking of weird, White talked up experiments that ISU has been running: burying men’s briefs and then digging them up weeks later. Since soil microorganisms need carbon to survive and the skivvies are high in carbon, the better soils spawned “Tighty Whiteys” that were in tatters, as White’s Power Point slides showed in what might have been a TMI moment for some onlookers (see the Wines & Vines article: “Underwear Goes Underground.”).

The point, though, is to get microbes working in the soil. After all, White said, “there are more microorganisms in a teaspoon of healthy soil than there are people on Earth.”

Forging an identity
In his keynote address, Frost, the only American with both Master Sommelier and Master of Wine certification, posited the question “Is there a Midwest wine identity?”

His answer: not yet.

“When I say ‘Cabernet,’ people know what it is,” Frost said. “But when I say ‘Le Crescent,’ people, even those in this room, can’t say exactly what it is.”

He praised the establishment of the Upper Mississippi Valley AVA and efforts to create more AVAs in cold-climate regions, citing an earlier revelation by Paul Tabor, of Tabor Home Winery in Baldwin, Iowa, that bottles with the AVA on the label sold more briskly and for $1 more than others. “Tell me who you are and where you come from. That helps,” Frost said. “You need to think not just about who I’m selling it to but who I’m making it for.”

Increasingly, he said, that would be a Millennial generation that eats out more often than any other age group. Getting local wines into these restaurants is essential. “Farm-to-table restaurants should work as farm-to-glass,” Frost said. “That has not been happening in the Midwest.”

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