Iowa wine scientist studying how to make better red wine from cold-hardy grapes

Iowans may buy more white wine than red, but that hasn’t stopped Iowa winemakers from wanting to produce better reds from the cold-hardy grapes that grow in the Midwest.

After all, the state has more than 60 wineries and reported selling 167,400 gallons of native wine in fiscal 2021, up 59 percent from the previous year.

Aude Watrelot, an assistant professor and extension enology specialist at Iowa State University, is leading a study that recently got an $11,577 state grant to develop best practices for improving the quality of red wine made in Iowa. She recently spoke with The Gazette about her research.

Q: You are from France, the hub of world wine culture. How did you get involved in researching wine?

A: “A lot of people think because I’m French I used to work on wine. I wasn’t working on wine at all. I was mainly looking at interaction of phenolic compounds and pectin. After my Ph.D., I wanted to work on those compounds and on another model. I did a postdoc (postdoctoral degree) in California, so I spent four years working with wine there.”

Q: Why is so little known about the chemical composition of grapes grown in the Midwest?

A: “In the harsh cold winter we have in Iowa we can’t grow pinot noir or cabernet sauvignon. So we use cold-hardy interspecific varieties — many developed at the University of Minnesota — that are resistant to cold winter and late spring frost. The main reason we don’t know so much about cold-hardy grapes is that they are pretty new. It’s also something rare, unique to northern states and Canada.”

Q: What are the challenges with producing high-quality red wine from these grapes?

A: “In red wines, we don’t have a lot of tannins, which are a type of phenolic compound. They are important for taste, texture and color, but also to protect against oxidation. A study the institute (Midwest Grape and Wine Industry Institute at ISU) and Iowa Wine Growers Association did found 40 percent of Iowa red wines showed a fault in oxidation.”

Q: What is involved in your study of Iowa red wines?

A: We are using finished wines from 2013 to 2020. We really wanted to have 100 percent Marquette or Frontenac grapes, so we reached out to different wineries to see what they have from those years. We evaluate the chemistry of the wine and the phenolic compounds. We’re trying to identify what we can do at bottling to have a good wine after one year or five years.

Q: So you’re looking at aging, which is after the wine is bottled. Is that different from maturation?

A: Everything that happens before being in a bottle is called maturation. Usually it matures in tanks or in barrels. In some places in Iowa they use oak barrels, but that is very expensive. They mainly use stainless steel tanks, but some winemakers add oak chips and/or tannins to enhance the flavor, color and texture.

Q: Could cold-hardy grapes be bred to include more tannins if they are critical to avoiding oxidation?

A: The University of Minnesota and Cornell University in New York constantly breed new varieties to have a different aroma, sugar or acidity. They are mainly working on the aroma compounds because that’s very important when you’re tasting wines. I don’t know if they are specifically working on phenolic compounds.

Q: As an extension specialist, do you get to work with Iowa winemakers?

A: That’s part of my job too. I’m doing some research, but that’s mainly applied research that is applicable to winemakers in Iowa and the Midwest. I’m always trying to provide workshops to winemakers, to help them improve the quality of wine. We will have two in-person workshops for Iowa winemakers this spring, March 17 and April 9.

Comments: (319) 339-3157; erin.jordan@thegazette.com