Fine-Tuning Grapes For Iowa’s Wine Industry

16:48 minutes

Plump purple grapes growing on a vine
Marquette grapes. Courtesy of Erin Norton, Midwest Grape and Wine Industry Institute, Iowa State University

Did you know that almost all the wine we drink, no matter what color it is or where it’s produced, comes from a grape species called Vitis vinifera? But these grapes can’t survive the cold, harsh winters of Iowa, so researchers at Iowa State University are growing special varieties that can withstand a wider range of temperatures. Through this effort, they’re even hoping to expand Iowa’s wine industry.

Onstage in Ames, Iowa, Ira talks with Dr. Erin Norton, director of the Midwest Grape and Wine Industry Institute at Iowa State University. They chat about the science of growing cold-hardy grapes, taste a selection of Iowan wines, and explore the basics of viticulture.

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Segment Guests

Erin Norton

Dr. Erin Norton is the director of the Midwest Grape and Wine Industry Institute at Iowa State University in Ames, Iowa.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow live from Iowa State University in Ames, Iowa.


I don’t know about you, but after a long day’s work, possibly right up here on the stage, I like to relax with a nice glass of wine. Among my favorites is a nice pinot noir– nice pinot. And that grape, pinot noir, in most of the wine we drink, no matter where it’s grown in the world, is a species called Vitis vinifera. And those grapes can’t survive the cold winters here in Iowa. That’s why researchers at Iowa State are growing special grape varieties that can survive the variable temperatures.

And joining me now to tell me all about the science of Iowa wine is my guest, Dr. Erin Norton, director of the Midwest Grape and Wine Industry Institute at Iowa State University based right here in Ames, Iowa. Welcome to Science Friday.

ERIN NORTON: Thank you.


IRA FLATOW: I never thought of Iowa as wine country.

ERIN NORTON: Most people don’t. I surely didn’t before I arrived as well.

IRA FLATOW: So how long have Iowans been growing wine grapes here?

ERIN NORTON: Iowa actually has a very rich history in grape growing, dating back into the mid-1800s. And we were actually sixth in the nation in 1919 for grape growing.


ERIN NORTON: Sixth in the nation in 1919. Now, after this, Prohibition, of course, came into effect, and so there are some other factors that led to the decline of the grape and wine industry. But around the year 2000, some new grape varieties were released, and that really encouraged the Iowa grape and wine industry to kick-start again, and we’ve been going strong ever since then.

IRA FLATOW: So you can’t grow every kind of grape here, right?

ERIN NORTON: No, we cannot in Iowa and, I would say, the upper Midwest. It’s just too cold. That’s the main factor that prevents us from growing these– I call them the European grape varieties. So there’s no pinot noir, no chardonnay, no merlot. It would not survive here.

IRA FLATOW: So what do you have here?

ERIN NORTON: So what do we have? We grow interspecific cold-hardy grape varieties. So interspecific meaning that researchers and also private breeders and mostly researchers up at the University of Minnesota have been working on this for a while, and they took Vitis vinifera grapes and native North American grape varieties– so Vitis riparia and things like Concord and Vitis labrusca– and breeding them together to get what we call interspecific. So they’re hybrids. Hybrids is a positive word in a lot of other industries. Not always as well known in the grape and wine industry.

IRA FLATOW: Now, what makes them able to survive?

ERIN NORTON: It’s really that native North American grape variety background in their genetics that allows them to survive the cold winters. And it also does provide as well some help with disease resistance and allows those grapes to survive here in the upper Midwest.

IRA FLATOW: Now for the most fun part of the day here. You’ve brought some wine.

ERIN NORTON: Yes, I did.

IRA FLATOW: Tell us what you’ve brought with you.

ERIN NORTON: Iowa State University has a small commercial winery now, and we have three wines today from two different varieties. So up at the Horticulture Research Station, we grow Marquette and La Crescent. So Marquette is a red grape. And we were talking about Vitis vinifera being part of the background. Pinot noir is actually a grandparent of Marquette. So we like to talk about Marquette being like pinot noir in its flavors and structure.

IRA FLATOW: So I have in my hand this beautiful, red– it’s a Marquette?

ERIN NORTON: It’s a Marquette, yes.

IRA FLATOW: You have to do that wine-snob thing with me now, like move it around.

ERIN NORTON: Sure. Yes, so swirling is an important thing, and there is a reason behind it. If anyone wants to learn how to swirl, the first, I would say, thing to do is do it on a table. It’s much easier on a table, and you can impress all of your dinner guests.

And the reason that we’re swirling our wine is to release the volatile aromatics. So there’s lots of smelly things in wine, and in order for them to get into your nose, they need to be in the gaseous form, and so you need to get them out of that liquid. And so swirling it helps to get them up and out of there, and then we sniff. And I could sniff for forever.

IRA FLATOW: Well, let’s eat your hearts out there in the audience.

ERIN NORTON: I know. Yeah, I’m sorry, everyone.

IRA FLATOW: Then when do we taste it?

ERIN NORTON: Once you’re satisfied, and if you’re–


IRA FLATOW: I’m no dummy. I want to get to the good part.

ERIN NORTON: If you’ve evaluated the wine and you think you’re happy with the smell of it, you can put a small amount into your mouth. And what I usually do when I’m wine tasting as a professional, swishing it around. And what that’s doing is, yes, you’re going to taste the wine, but you’re also going to smell the wine while it’s in your mouth because those aromatic compounds are going to go up the back of your mouth into your nose, and that gives us flavor. And so those retronasal aromas give us the flavor of the wine.

IRA FLATOW: Let’s do it. Oh, you didn’t drink your whole thing like I did.


ERIN NORTON: That’s OK. And what did you think?

IRA FLATOW: This was delicious.


IRA FLATOW: This really–

ERIN NORTON: I’m so glad.

IRA FLATOW: –is delicious. I don’t know how to describe, not too fruity but overall aromatic. I don’t know how to do those sorts of things. I just know it really tastes good.

ERIN NORTON: That’s a good place to start. It does take training and practice.

IRA FLATOW: Yeah, I have to say, I’m very surprised how good that tasted.

ERIN NORTON: A lot of people tell me, oh, I’m pleasantly surprised. And that’s actually one of my– I’d like people to not be pleasantly surprised that we can produce these kinds of wines in Iowa.

IRA FLATOW: It was delicious.

ERIN NORTON: Oh, great. Thank you.

IRA FLATOW: It was delicious wine.


IRA FLATOW: Can you grow these grapes in other parts of the country, not just here?

ERIN NORTON: Yes, so we are hearing and seeing about growing in Washington state, and in Canada as well, they’re growing quite a bit of these grape varieties. And British Columbia, actually, they have a significant grape and wine industry and really got wiped out with winter damage the past couple of years, and we’ve heard that they’re planting these grape varieties.

IRA FLATOW: And what’s in the chemicals that give wine its taste, this different, distinct tastes?

ERIN NORTON: So the chemicals are right in the grapes themselves. One thing to note, when I’m saying that there’s floral or tropical or, even more specific, strawberry, we don’t add any of those things. They just happen to grow within the grapes themselves, and it just it comes out as a note in the final wine.

IRA FLATOW: So what needs to happen? I mean, it sounds like you have a very successful industry going here. What’s the future look like?

ERIN NORTON: So we have about a hundred wineries here in Iowa.

IRA FLATOW: A hundred?

ERIN NORTON: A hundred wineries, yep. And so where do we go from here? So we’ve had hundreds of years of growing Vitis vinifera, and we really know how to make the best wine from those types of grapes and how to treat those grape varieties. And so that’s really what we need to figure out is, how do we make the best La Crescent possible? Should it be the style that we’re currently making it? Could it be a sparkling wine? Could it be an iced wine or things like that? So there’s a lot of work to be done, but there’s also a lot of work to be done to understand these grapes on a fundamental level and, what are the differences chemically between these grapes versus the Vitis vinifera?

IRA FLATOW: Or how much sunlight they might need, right?

ERIN NORTON: Exactly, yes. So how do we grow them best as well? Because I will say growing these grapes is completely different than growing the Vitis vinifera varieties.

IRA FLATOW: Is that right? Tell me what you mean by that.

ERIN NORTON: A lot of these grapes like to grow up high. And so Vitis vinifera, if you go to vineyards around the country or around the world, usually the grapes you’ll see at waist level, and then the shoots like to grow up straight. The grape varieties that we grow here mostly have recumbent growth. So the grapes are all the way up high on the top of the wire trellis, and then the shoots like to grow downwards.

And so there are some mechanical mechanization challenges and labor challenges with that as well as sun exposure. So we do like to expose the grapes to sun.

IRA FLATOW: What does the sun do to the flavor?

ERIN NORTON: So the sun helps to promote the mechanisms to create those flavor compounds, and those flavor compounds are really the last to develop in the season, but we need to get those mechanisms, those pathways started as early as possible.

IRA FLATOW: Let’s go to the questions over here. Yes?

AUDIENCE: About how long does it take to grow the grapes?

ERIN NORTON: That’s a great question. So when you plant a vine, when you buy a vine and you plant it, it does take about three to four years to get a crop off of it. And remember that these are perennial crops, meaning that we put a vine in the ground, and we probably keep it there for at least 20-plus years. So we really have to take care of these plants.

And so it takes about three or four years to get a crop off of them, and every year if you’re treating your vines properly and doing proper viticulture– which is the science of vineyard management, of working with the vines. If you’re doing that properly, you should be able to get grapes off of them every year.

IRA FLATOW: Are there any drawbacks to using these cold-resistant varieties in terms of the flavor you get here versus the other kinds of grapes?

ERIN NORTON: Yeah, and explaining those flavors to consumers, some of them, just they’re different. I think if you tasted the La Crescent, for example, it’s hard to compare those to the other varieties. They’re just, there’s different flavors.

IRA FLATOW: Well, yeah, because I noticed these are lighter tasting. They’re not the heavy kind of California wines that you might get.

ERIN NORTON: Right, especially the red wines. So a lot of the consumer market right now really loves big, bold, heavy red wines. The grape varieties that we’re growing in Iowa are just not cut out for that.

IRA FLATOW: Because of?

ERIN NORTON: So we’re lacking in tannins. So inherently, the tannins are low in these grape varieties, and part of that is because of the North American characteristics. We’re also not able to extract and retain those tannins into the wine. There are some chemical challenges with the makeup of these grapes. That’s part of the research that we’re doing in my labs right now is trying to overcome those challenges.

IRA FLATOW: Speaking of challenges, let’s go right here. Yes?

AUDIENCE: Where can you get the varieties of grapes that you mentioned?

ERIN NORTON: Where can you get them? So these grapes, you probably won’t ever see them at a grocery store. They’re not table grapes. So wine grapes are actually a lot different than table grapes in that they’re quite a bit smaller, and they have a big seed in them. They’re not great for people to be eating them.

IRA FLATOW: I sort of detected a slight Canadian accent.

ERIN NORTON: Did I say out?

IRA FLATOW: You did a few times. I love it. I love it. But they let the grapes freeze, right? Do you do that here?

ERIN NORTON: No. We make ice wine. Actually, it’s my hometown where ice wine is produced in Canada, in Niagara. The grape varieties that they’re using for ice wine are not the same grape varieties we’re growing here. Unfortunately, the weather conditions would lead to rot here before we would be able to get a hard freeze. So there are several places in Wisconsin trying ice wine, but in Iowa, we just don’t get that hard freeze fast enough.

IRA FLATOW: Let’s go to the questions over here. Yes?

AUDIENCE: How long does it take to make wine?

ERIN NORTON: That’s a great question. So we harvest here in Iowa. We harvest our grapes towards the end of August, beginning of September, and that’s a little bit earlier than a lot of other regions. For myself here at the Iowa State University winery, we are finished bottling in March, and so that’s about the amount of time it takes to go from juice to wine. The fermentations usually last between 7 to 14 days. So it’s not terribly long.

IRA FLATOW: Yeah. And we know that Iowa has some of the best, if not the best, soil for growing. How does that affect the grapes as opposed to maybe Minnesota or Wisconsin or some other place?

ERIN NORTON: Yeah, that’s an interesting one. Grapes actually don’t need super fertile soil.

IRA FLATOW: They don’t?

ERIN NORTON: A lot of the famous wine regions around the world, they have more rocky soil, or the grapes really have to go send their roots down deep to find the water and find the nutrients, and that kind of struggle in the vines means that they put more effort into their fruit, and so they get really great-quality fruit.

Here in Iowa, really fertile soil. The grapevines here put a lot of effort into their leafy canopy, and so that is a challenge for us to deal with. And it’s more labor, more work in the vineyard to balance the vines between leaves and canopy so that the fruit can ripen appropriately.

IRA FLATOW: Do you collaborate with other winemakers?


IRA FLATOW: Tell us about that.

ERIN NORTON: On a daily basis. And so I’m constantly– part of our work is working with the industry and teaching them how to make wine but also finding out from them what challenges they’re having and developing either educational programs or resources for them or research projects, if they’re having a problem– for example, the tannin if a winemaker came up with an idea to freeze the grapes to try and break the cells and let some of those tannins be extracted more easily. And so we took some of his samples that he had done and analyzed them to see if that was, indeed, a good idea.

IRA FLATOW: I remember when Napa Valley got on the map, so to speak. It wasn’t until, what, the 1970s where we heard about that. Where is Iowa in terms of its 1970s moment? Are we in the ’50s now or where are we?

ERIN NORTON: I don’t know if we’re going to have our own Judgment of Paris, but, I mean, that would be great. I am constantly trying to get our wines in particular out to competitions so that people can taste them around the country and not just here in Iowa.

But I do think we’re at this point where we have about a hundred wineries, and that’s been stable for a while. And so it’s a maturing time for the industry. And I think what will push us past that is just to continue to make quality wines and to work together to raise the awareness of the industry.

IRA FLATOW: One last question. I’m going to give you my blank-check question I give some researchers, and that is if you had an unlimited budget, if you had a blank check, what would you use it on? Where would it best be spent in your research or what you need to know or want to know about the wine industry, making wine, fermentation that you don’t know now?

ERIN NORTON: I had a conversation earlier today about genetic markers, whether they’re using genetic markers to breed better wine grapes.

IRA FLATOW: What do you mean by that?

ERIN NORTON: So there’s genetic markers that we can target to see where certain molecules are being made in the grape and whether you can turn those on or turn those off or express them more or things like that. And I’m not a geneticist, but I would love to be able to go and work with the breeders to say, we need this. We need tannin, or we need less acidity. Let’s work together to– designer grapes, I suppose. Hopefully that would catch on with winemakers, but I think to design better grapes for the climate, the coming climate, would be great.

IRA FLATOW: Well, if you need anybody to help you test out the results of that engineering, please get back to me.

ERIN NORTON: You’re my guy.

IRA FLATOW: Thank you very much, Dr Norton. Dr. Erin Norton, director of the Midwest Grape and Wine Industry Institute at Iowa State University.

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