Cold Hardiness, White Wine Quality
Cold Hardiness System Gives Growers a Warm Feeling
Using a sophisticated system they designed, WSU viticulturist Markus Keller and his team are measuring the cold hardiness of grapevine. The system allows them to collect data from buds and wood pieces from a range of grape varieties in order to determine “critical” temperatures (the temperatures at which the tissues freeze and are killed) for each variety.
The system is now being used as a model for programs working in grapes and other crops around the world.
Each week the team adds new information to their Web site, which growers use to track the changes in cold hardiness throughout the winter season. Based on this information, growers can decide whether to run their wind machines or use other measures of frost control.
This year, for the first time, Ste. Michelle Wine Estates is participating in the project. Ste. Michelle viticulturists collect samples from their extensive variety collection each week, and that information is used to supplement samples collected by Keller’s team.
The service is funded by WSU, the Washington Association of Wine Grape Growers through the Washington Wine Industry Foundation and the Washington State Concord Grape Research Council.
From Vine to Wine, New Research Spurs Quality
Ask a wine expert what makes a great glass of wine and they’ll answer: good fruit. Now, three Washington State University scientists have begun research on the effects of vineyard nutrient management on wine quality as a result of the U.S. Department of Agriculture’s new Specialty Crops Research Initiative Grant.
Project director and WSU professor Joan Davenport, food scientist Kerry Ringer and viticulture extension specialist Mercy Olmstead have teamed up with three scientists from Cornell University to conduct their research.
Davenport said the project objective is to connect stakeholders and scientists through a series of meetings to develop an interdisciplinary multi-state team to study the impact of nitrogen management on all aspects of growing white wine grapes.
The team will investigate plant nutrient management options for enhancing flavor and aroma compounds in white wine grapes, as well as explore options for assuring adequate nutrients for fermentation while at the same time discouraging aspects that may adversely affect vine health, such as fungal diseases or insect pests.
Davenport said studying nitrogen management on white wine quality, which is one of the main goals of her research, is not a simple task.
“What’s tricky is that too much nitrogen can make the grapes grow too vigorously and taste bad,” Davenport said. On the other hand, she added, insufficient nitrogen can cause problems with the yeast production that grapes need in order to grow properly.
Ringer said she hopes to have a better understanding of how to manage nitrogen with aromatic white wine grapes in particular, since most of her research in the past has revolved around aroma compounds.
“We want to make better-smelling wine for the consumer,” she said.
Nutrient-management research is currently being conducted on white wine grapes in vineyards in central Washington and the Geneva area of New York, Davenport said. For now, Davenport and her team are focusing on identifying wine-grape growers and asking them about their nitrogen management practices. Davenport said the long-term goal is to formulate recommendations for growers based on her team’s research that would give North American-produced white wines a competitive advantage in the world market.
The meetings will be held in conjunction with the annual Washington Association of Wine Grape Growers meeting in February, the annual Finger Lakes Grape Growers meeting in March, and the American Society of Enology and Viticulture Eastern Section meeting in July.
“We want to help the U.S. come up with a product that consumers want to buy over (products from) other countries,” Davenport said. “We want the U.S. to be number one.”
Ultimately, Davenport said she wants to help produce the highest quality product “from the vine, to the bottle, to your table.”
Marketing and News Services Intern