December 2008 Issue of Wines & Vines

Farming for Aromas

Connecting the dots between viticultural methods and wine's sensory attributes

by Tim Patterson
Bonterra vineyards
Andrew Reynolds of Brock University will discuss the effects of viticultural practices such as canopy management (above) on wine during the day-long Aroma Symposium on Jan. 30.

  • Unified is dedicating an entire day of sessions to an Aroma Symposium, with talks by international viticulture experts.
  • Growers change their viticultural practices for a number of reasons--from neighbors' suggestions to scholarly studies.
  • The trick to managing crop load is balancing yields with quality, researchers say.

    Aroma Symposium Jan. 30, 7:30 a.m.-5 p.m.
The all-day program that concludes the upcoming Unified Symposium is billed as an Aroma Symposium, which probably conjures up an image of endless lists of volatile compounds and a tour through their chemical precursors and sensory thresholds. But not this time: This symposium is all about vineyards--the place where great wines are made, or not.

"I really think of this as an examination of viticulture and wine quality," says Andrew Waterhouse of the University of California, Davis, who organized the program and recruited the list of international speakers. The connections, real and imagined, among various vineyard practices and resulting wine characteristics has always been a subject of speculation and many opinions; this symposium tries to draw on the results of careful, rigorous studies to sort out what works and what doesn't.

Wine Bottle
Initial, broad presentations will cover the conversion of various grape components to wine aromas and a survey of the viticultural parameters affecting wine quality. Subsequent detailed presentations will look at water deficit and wine quality, ripening patterns and their sensory results, the impact of crop levels, the effects of leaf removal, and the role of vine microclimates. Results to date from an ambitious New Zealand program to trace Sauvignon Blanc "from grape to glass" will be offered, and two of the presentations will be accompanied by tastings. Overall, the sessions will try to connect the dots between farming methods and sensory attributes.

From the ground up--and down

Andrew Reynolds of the Cool Climate Oenology and Viticulture Institute at Brock University in Ontario, Canada, will handle the overview of viticultural parameters--canopy management, trellising, vine spacing, irrigation--and what we know about their effects. A good deal of research has been done on this by a number of research organizations. Much of it, Reynolds says, has followed through to see what are the sensory outcomes of this or that practice.

In reality, however, Reynolds says that people change their viticultural practices for any number of reasons. "One reason might be that they know or firmly believe it's going to work, based on research, extension publications, etc.--something objective. A lot of the time people will change practices because of fashion, because their neighbors are doing something they were told will work. I see a lot of that. We have some boutique wineries here (Ontario) saying to their growers that they have to drop their crop to 2 tons per acre or less--but there is no reason it has to be that low, besides a belief. Belief systems in viticulture and enology are just as strong as those in world religions."

unified symposiym
The symposium will cover the aromatic results of water deficit, ripening patterns, leaf removal, crop levels and climate.
Limitation of crop load is a constant theme in discussions of how to grow high-quality grapes, but the evidence, according to Reynolds and many other researchers, doesn't make things look so simple. "Grapevines are a balance situation. Too much crop can't be matured without enough leaf area; but drop too much crop, and you have too much vegetation. Drop beyond a certain point, and you get huge increases in veggie character as well."

Canopy management--trellising systems and leaf removal--is another area where conventional wisdom can get out of sync with reality. "In cool climate situations," Reynolds says, "leaf removal can really have a positive effect, but most of the work on canopy management and training systems evolved in cool climates, and when these ideas got adopted in North America, sometimes in much warmer climates, they haven't always worked. More than one grower in California has discovered that extensive leaf removal can promote sunburn, not grape quality."

The symposium won't answer every question, but it should offer good food for thought and some cautionary lessons about assuming that the latest thing is automatically the best thing in every situation.
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