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Uncorking the Science Behind Quality Wines

Inside a sensory lab at Iowa State Uni­versity, a group of five volunteers sit in silence inside their own white-paneled booths. They aren’t allowed to talk or look at the other volunteers sitting in the booths next to them.

Once they settle in, a tiny door opens up in each booth, and a researcher on the other side of the door hands them a single glass of wine.

The door closes, and the panelists take their time sipping and analyzing. They identify the different flavors of the wine (Does it taste floral? Do I detect a hint of apricot?) and jot down their observations on a score sheet. Then they flip a light switch to indicate that the researcher can take the wine glass away.

The tasters repeat the process until all the wines are tested — sometimes up to a dozen wines in one day. And if you’re wondering, the volunteers are encouraged to spit out the wine in a paper cup after tasting so they don’t get too tipsy to judge.

The researchers behind the doors work for the Midwest Grape and Wine Industry Institute at Iowa State University (ISU) in Ames.

The institute, the first of its kind in the Upper Midwest, partners with wineries and vineyards in Iowa and across the country to help improve the quality of their wines and establish their businesses.

Dr. Murli Dharmadhikari, director and Extension enologist, came to ISU to launch the Midwest Grape and Wine Industry Institute back in 2007. Dharmadhikari previously worked in Missouri, where he helped establish the Show-Me State’s award-winning wine industry.

Joining Dharmadhikari’s team are Tammi Martin, administrative specialist, who manages the in­stit­ute’s activities and com­munications; and Jennie Savits, a research as­sociate who started working at the institute when she was a food science undergrad at ISU.

Over the last decade, the number of wineries in Iowa has rapidly grown from a few dozen wineries to about 101 wineries today. And the wineries aren’t just in urban areas. Nearly every county in Iowa is now home to at least one winery. (Find an updated map of Iowa wineries at http://www.extension.iastate.edu/wine/.)

Many of these winery owners start making wine as a hobby in their basements and then decide to turn their hobby into a business. Some are farmers who are growing a few grapevines in addition to corn and soybeans. Others are building a winery to bring their sons and daughters back home to help run a family business.

The Midwest Grape and Wine Ins­titute can assist start-up wineries in determining what equipment they need to produce and bottle wine. The institute also offers lab testing to help wineries determine if their wines meet industry- and consumer-accepted quality standards.

“When a new winery comes along, we reach out to them so they know that they can use our services and take advantage of what we have to offer to get them off on the right foot if they need any assistance,” Martin explained.

Dharmadhikari said it can take up to 10 to 20 years for a winery to find the right balance of grape and wine varieties.

“The wine industry usually takes a generation to establish the business — and the second and third generation benefits the most,” he said.

Dharmadhikari credited the new cold-hardy grape varieties, developed by the University of Minnesota in the early 2000s, for sparking the rapid expansion of Iowa’s wine industry.

The University of Minnesota varieties — named Frontenac, Frontenac gris, La Crescent and Marquette —are a hybrid of European wine grapes and native grapes, such as wild riverbank grapes, Savits said.

The cold-hardy grapes can tolerate winter temperatures as low as negative 30 degrees Fahrenheit, unlike European and California wine grapes, which typically can’t survive below 20 degrees, Savits explained.

For her graduate research project, Savits analyzed the flavor and aroma profile of cold-hardy La Crescent grapes.

“A lot of growers are planting (La Crescent) and experimenting with it because it has some Muscado (grapes) in its heritage, so it’s very fruity and fragrant and people are thinking it might be a good signature wine for the state," Savits said.

“That’s why the research is so im­portant, because these grape (var­ieties) are brand new. We don’t know the chemistry, we don’t know the styles, we don’t know what to expect in terms of flavors and aromas. So there is a lot for everyone to learn. It’s pretty exciting.”

In addition to its focus on the science, the Midwest Grape and Wine Industry Institute works with Iowa winemakers to help perfect the art of crafting fine wines.

“That’s the most important part is the human perception … It’s how the wine tastes, how it smells,” Dharmadhikari said.

The institute conducts sensory train­ing workshops to help winemakers develop their palettes, or flavor-detecting abilities. Specifically, the training helps winemakers recognize when a flaw is starting to develop in the wine so they correct the problem.

“It’s like a reflexology-type thing, like athletes that train together to learn the basics,” Martin says. “So our athletes are really good with their noses and their tongues. It just becomes quicker and more accurate.”

The institute has also recruited 20 or so wine enthusiasts to volunteer for their taste-testing panel. The volunteers must go through the sensory training and pass a test in order to be on the panel.

The taste-testing panel is part of a certification program for the Iowa Quality Wine Consortium. Mem­bers of the Iowa Wine Growers As­sociation (IWGA) are invited to vol­­untarily participate in the Iowa Quality Wine Consortium.
 
Each winery that joins the consortium can submit five samples to the Midwest Grape and Wine Industry Institute for analysis. The samples undergo a set of chemical tests to make sure they meet guidelines set by the IWGA. If the wines pass the chemical test, they go on to the taste-testing panel.

A wine “passes” the taste test if the panelists give it a median score of 13, on a scale of 20. “We use the Davis 20 point score card. It was a scorecard developed by (University of California-Davis), and we adapted it to focus a little bit more on faults, because we really want to make sure that good, clean wines are coming through,” Savits said.

Wines that pass the chemical and sensory testing receive the official Iowa Quality Wine Consortium seal, which wineries can place on their bottles.

“At first, (taste-testing) was a chal­lenge,” Dharmadhikari admitted, "but now it’s a pleasure. The quality of the wines in the state are getting better and better.”

Dharmadhikari also noted that the Iowa wine industry has become an economic driver in the state. A recent analysis, commissioned by the Midwest Grape and Wine Industry Institute, found that Iowa’s wine and grape industry contributed $420 milli­on to the state’s economy in 2012, an increase of 80 percent from $234 million in 2008.

“It’s really helped revitalize small communities,” Savits said. “We see in places like California and Europe where wineries are bringing in tourists and spas and resorts. There’s really no reason why this can’t happen here.”