A good year for Minnesota wine grapes

Paul Huttner and John Thull at the University of Minnesota Horticultural Research Center . Image: Paul Huttner/MPR News.

Minnesota may not be known as wine country just yet. But as our climate trends warmer, northern wine growers are having some success.

It turns out 2017 was a good year for Minnesota wine grapes.

This week I spoke with Minnesota wine guru John Thull from the University of Minnesota Landscape Arboretum. John develops grape varieties and tends the grapes from start to finish as a researcher at the Horticultural Research Center in Chanhassen.

MN Arboretum HRC John Thull w vines
John Thull with the grapes at the University of Minnesota Horticultural Research Center . Image: Paul Huttner/MPR News.

Severe weather challenges

2017 brought plenty of severe weather to Minnesota. But John tells me via email the wine grapes rode the storms out pretty well.

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On June 11th, we had that fast moving storm blow through with hail. The vines were beat up with shredded leaves and broken shoot tips, but the grape flowers were just at the bloom stage of development. The hail broke off some flower clusters but many just deflected and came through just fine. The vines recovered and looked good again with in a few weeks.

Apple trees had already formed fruit by June 11th. John notes the hailstorm had a much bigger impact on the 2017 apple crop.

The apples were another story. Most of the tiny developing apples were hit multiple times leaving little dings that would stay on the apple skins for the rest of the season. If growers made it through the June 11th hail storm, there were a few other opportunities to get nailed in July and even in September.

A Mediterranean summer? Deeper reds

Summer in the Twin Cities was temperate. Temperatures started warm but cooled over time. Overall the summer was close to average in the Twin Cities, running just 1.5 degrees warmer than average overall.

June temperatures averaged 2.5 degrees warmer than average at Minneapolis-St. Paul International Airport. July was just 1.5 degrees warmer than average. Then a cooler weather pattern took hold in August. August temperatures were 2.5 degrees cooler than average at MSP Airport. It marked just the second month in two years with below average temperatures in the Twin Cities.

The temperate summer and late season coolness may have contributed to deeper reds and more flavorful grapes. John elaborates on how summer temperatures may have impacted grapes this year.

August was a relatively cool month, which put the breaks on the ripening.

The overall humidity and night time temperatures seemed to be lower all the way through this season. The ripening has been slow and late this year, but the overall quality of flavors has been good, especially for the red varieties. The color development was darker than we've seen in many years, maybe related to the cooler night temperatures.

It will be interesting to see just how much this summer's favorable wine weather shows up on the taste buds in the 2017 wine vintage.