Campus News

Published by Communications and Public Affairs (519) 824-4120, Ext. 56982 or 53338

News Release

August 01, 2001

Want the best wine? Let there be light, U of G researcher says

Whats the secret to producing the best-tasting wine? Researchers at the University of Guelph say its simple: let there be light.

Graduate student Justine Vanden Heuvel, along with her advisers, plant agriculture professor Alan Sullivan and Helen Fisher of the Vineland Research Station, studied more than 2,000 vines. They found that the most-flavourful wines came from grapes grown on modern trellising systems that maximize light to the fruit, producing more grapes and heightening their flavour.

I hope my research will give grape growers in all cool climate areas a better understanding of how to grow grapes that will make high-quality wine, said Vanden Heuvel, who examined the vigour and yield of the vine and the quality of the fruit and wine.

Historically, it was thought that a higher yield of grapes meant lower-quality fruit. That thinking changed after a series of studies in the 1980s showed that the amount of fruit on a vine is not an indicator of quality. Since then, emphasis has turned to controlling the vigour of a vine, which is the size of the vine and its productivity. Trellising is one way of doing so; it involves manipulating the architecture of the vine to control vigour and increase the light to the grape clusters, Vanden Heuvel said.

High fruit quality depends on light exposure on clusters, because light exposure allows the fruit to accumulate sugar (sugar is an important measure of fruit quality since it directly translates to alcohol level during fermentation).

Vanden Heuvel is examining the density of the vine using a light sensor to measure the penetration of light into the internal vines of the plant. Her comprehensive study includes four traditional trellis systems and two of their modern counterparts. The more traditional trellis systems that have been used for hundreds of years tend to run parallel to the ground and concentrate the fruiting zone so that all of the fruit grows in the same area, she said. More modern systems tend to run perpendicular to the ground and allow the fruit to be more equally distributed.

Vanden Heuvel has discovered that modern trellis systems increase grape quality because they allow more light penetration to the vines. She tested the trellising systems for two cultivars, the white grape Chardonnay and the premium red wine grape Cabernet Franc.

Ill be able to tell grape growers why certain trellising designs function better for both productivity and wine quality, she said.

Vanden Heuvel has been invited to present her current findings to the American Wine Society in South Carolina in November.

Justine Vanden Heuvel
Department of Plant Agriculture
(519) 824-4120, Ext. 6165

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Lori Bona Hunt,
media relations officer,
(519) 824-4120, Ext. 3338.

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