One out of 10,000 vines fruits a cotton-candy-flavored grape.
Another produces a grape with a pineapple tang, and a certain dud vaguely tastes of green bell pepper.
Through years of testing, hands-on labor and patience, grapes grown at the University of Minnesota’s Horticulture Research Center in Excelsior, Minn., have become a part of a Midwestern resurgence in fruit breeding set in motion in the ’80s.
A new grape variety, MN 1285 — created to withstand the state’s cold climate while remaining suitable for Minnesotan wine — is nearing the end of its roughly 20-year testing and naming period.
At the start of every fall, University vineyard managers and husband and wife John and Jenny Thull spend their days harvesting ripe grapes, keeping an eye on prospective cultivars and tagging unsuccessful vines for chopping.
About 40 percent of the University’s 11-acre vineyard was planted in 2007, said Matt Clark, an assistant professor in grape breeding and enology — the study of wine.
Most of the school’s vines are dedicated to cultivating cold-hardy wine grapes, which thrive in Minnesota’s cool nights and hot summer days and can’t be found in warmer climates, like in California.
“I think people are romanced by the idea of growing grapes and making wine,” Clark said.
On an autumn harvesting day, Clark joined the Thulls in tasting grapes one-by-one to check for subtle flavors, good and bad, that could set the variety apart.
“The acids are really high, really tart, but the flavors are so strong,” Clark says, popping a grape in his mouth. “It just provided something interesting that you’d never get in a supermarket.”
Picking the best grape
The last time the University of Minnesota introduced a new grape was in 2006, with the debut of the Marquette variety.
Within the next two years, the University plans to release MN 1285, which doesn’t yet have a name, said Anne Hall, technology strategy manager for the University’s Office for Technology Commercialization.
Nurseries licensed to grow University grapes work with OTC to ensure the plants are growing properly and turning out quality fruit, OTC venture development executive Thomas Hutton said.
“The breeders tend to have looked at something … for quite a while before they’re really thinking that it has commercial potential,” Hall said, at which point they tell OTC about the new variety.
The MN 1285 grape was introduced to OTC about two years ago, Hall said, and is expected to hit the market for licensed growers in 2017.
Since the late ’70s, the University has created half a dozen new kinds of grapes, four of which were designed for wine. Despite the introduction of two table varieties since the ’70s, an untapped demand in that market still exists.
“There’s definitely a need or a want out there for those hardy table grapes,” John Thull said.
But it’s complicated to produce a cold-hardy, seedless table grape — like the ones sold in grocery stores that come from Mexico and California. That’s why the University’s grape program has largely focused on creating wine grapes.
To determine a grape’s desirability, growers check for robust flavor, acidity and sugar levels, ripeness, and ability to withstand disease. Then, growers observe the fruit over several seasons — provided the grape tastes exceptional and withstands the weather.
“Maybe after this year we say we don’t like it, or maybe after spring it dies to the ground, and this is the one time we’ve ever tasted it,” Jenny Thull said. “Which is always a possibility.”
And sometimes a vine is chopped after several seasons if it begins fruiting poor-tasting or disease-prone grapes.
This season, Jenny Thull axed an 11-year-old vine.
“It just has too many negatives at this point,” she said, marking its death sentence with an orange ribbon. “We have to make room for more cool things.”
When ripeness and sugar levels reach their peak, the Thulls harvest the grapes on that vine. The lot can weigh between 10 and 100 pounds.
Once harvesting season comes to a close, the vineyard managers prepare for pruning, which John Thull said is his favorite part of the process.
“You really got to think about what you’re doing. Each one is a puzzle, and you got to think about what’s best for the vine,” he said. “You have to remember what the vines endured in the past years, and you have to sort of anticipate what they can handle coming up, and that’s how you determine how to prune.”
Land of 10,000 grapevines
Since the state Legislature approved funding to build a research winery on the school’s grounds in the late ’90s, the vineyard has grown almost threefold, said Jim Luby, a University professor in fruit production and plant breeding.
And in the past five years, the number of wineries statewide has more than doubled, hitting about 70, Minnesota Grape Growers Association President Irv Geary said.
The University began experimenting with fruit breeding under the wing of researcher Peter Gideon in 1878, 20 years after Minnesota became a state.
When he retired 11 years later, the program deteriorated.
More than half a century later, in 1944, the first table grape was introduced at the University. Elmer Swenson — who is now known in the community as the “godfather of cold-hardy grapes” — jumpstarted the program in the ’70s by creating the Edelweiss and Swenson Red table grapes.
At that time, the school owned about three or four vineyard acres, Luby said. Now, it owns 11.
But the berries haven’t been as profitable as other University-developed fruits, namely the school’s reputed apples, Hutton said. Demand for the 1990 Honeycrisp spans the globe.
Even the program’s most popular grape breed, Marquette, hasn’t approached such success.
“I think there’s a very large emphasis on the apple program here,” Hutton said.
To keep the state’s grape-growing trend alive, Geary said local winemakers need to up their marketing efforts to convince Minnesotans to drink their own wine.
The Minnesota Grape Growers Association offers classes and community events, like an annual cold-climate grape-growing conference and a winter wine festival.
The number of wineries in the state exceeds the number of vineyards, which Geary predicts will cause a shortage of grapes in the near future. He said more commercial-sized vineyards will need to pop up statewide to fill the void.
Despite the growing industry, only 1 percent of wine consumed by Minnesotans is produced in the state, he said.
For a wine to be considered Minnesotan, it must be made up of at least 51 percent Minnesota grapes, Clark, the grape breeding professor, said.
“If we can get the Minnesota wine consumers to consume more Minnesota wine we will see our market go up. But I don’t know that we’ll ever be able to compete with California,” Geary said, adding that harsh winters can be devastating to Midwestern growers.
Minnesota’s cold climate fosters grapes that are crisp and acidic — a flavor he said is “in vogue” — in comparison to high-alcohol-volume wines coming from California.
Surveyed wineries statewide use mostly University grapes, Luby said.
It’s a matter of geographic oddity that Minnesota sits at approximately equal latitudes as some regions of France — a country internationally renowned for its wine grape varieties.
In the meantime, Hutton said OTC is working with countries like Canada and China to transport University vines across the border, though moving plant material overseas means surpassing strict laws that protect against the transfer of disease from one country to another.
From seedling, to grape, to wine
On the outside, the odds seem stacked against finding the perfect grape.
A hundred crosses between about 55 parent grapes yield something like 14,000 seeds, which are then carefully sifted through by researchers. Even then, only one out of 100 test grapes will become a grape variety.
That’s when University grape growers begin their arduous year-round work: cleaning and collecting data on the berries, protecting them from pests and making wine.
“I don’t think a lot of people are aware how plants [are grown],” Clark said.
When a seed shows unique and promising traits like disease resistance or balanced acidity, it’s crossed with another favorable seed to create offspring.
“Just like you or I, the seed inside the fruit is a unique genetic combination,” Clark said.
The parents’ creation is monitored closely to prevent cross-pollination with any other grapes. Once a seedling cross is pollinated to become young vines, it receives a spot to mature in the vineyard.
The year-round grape-breeding process heats up in spring, when flower buds peek through the vines’ brown shells. After several weeks, those flowers are pollinated by wind or bees and transform into miniature-pea-sized berries.
The fruit develops over the next months until late August brings the ripening sun, Clark said.
The young grape breed is monitored and allowed to cycle through several seasons before a fruit might bloom.
The entire breeding process, from seedling to named and licensed grape, can take about two decades, Clark said.
After grapes are harvested at the University’s Excelsior vineyard, growers clean the berries and press them for juice, he said.
The juice is left in a bottle overnight to settle, Clark said. Growers then transfer the juice to another bottle and discard excess pulp, skins, stems and seeds from white wine. The red wine needs the extra “junk” to retain its flavor and color, he said.
After growers set aside the wine for fermentation, it’s back to the vineyard to harvest another batch.
“Nice fruit, nice clusters, even ripening,” Clark says, observing a vine of grapes. “Maybe they’ll pick that one tomorrow.”