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Brock researchers trying to pin down terroir effect in Niagara


April 1, 2008
By Marg Land


Topics

Bring up the subject of terroir
among a group of wine growers, producers and consumers and you’re bound
to end up with a lively discussion with varying viewpoints and ideas.

Bring up the subject of terroir among a group of wine growers, producers and consumers and you’re bound to end up with a lively discussion with varying viewpoints and ideas.

There are as many interpretations of terroir as there are grape varieties. According to Wines of Canada, terroir “describes all of the influences on the flavours in the wine that come from where the vines grow, especially soil, climate, slope, the aspect of the slope.” Wikipedia refers to terroir as “the special characteristics of geography that give a wine its individuality. It can be loosely translated as ‘a sense of place,’ which is embodied in the qualities of a wine, the sum of the effects that the environment has on the vines which produces a particular wine.” Meanwhile, Terroir-France defines the term as “a group of vineyards (or even vines) from the same region, belonging to a specific appellation, and sharing the same type of soil, weather conditions, grapes and wine making savoir-faire, which contribute to give its specific personality to the wine.” Granted, these definitions are somewhat similar to one another but when it comes down to defining terroir, there is some controversy as to whether winemaking practices should play a role.

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Researchers with Brock University’s Cool Climate Oenology and Viticulture Institute (CCOVI) are continuing research originally started in 1998 examining the basis for the terroir effect on wine varietal type in the Niagara region. The group’s initial study, which ran from 1998 to 2002, involved separating soil texture effects, where they existed independently, from vine size effects. Wines were made from both low- and high-vigour vines located in both sandy and clay soil
portions of five different Chardonnay vineyards. The results showed very few consistent soil texture effects but some vine size effects, both consistent and explainable, were noted.

Some research was also performed involving spatial variation in a Riesling vineyard.

The group, headed by Dr. Andy Reynolds, is planning on continuing its research, this time examining water stress as a potential determinant of terroir.

“The layperson’s assumption is that water stress is beneficial to wine ‘quality’ but most grape physiologists (and growers) would agree that water stress can have many negative consequences, including diminished winter hardiness, delayed maturity, and reduced yields,” stated Dr. Reynolds in a research brief. “We are hypothesizing that we can identify consistent water stress zones throughout vineyard blocks and that we can demonstrate differences in berry composition and wine sensory attributes that are related to water stress.”

Ten blocks of Riesling and Cabernet Franc have been chosen, each representing one of the 10 sub-appellation regions being proposed by the Vintners Quality Alliance (VQA). As these 10 sub-appellations have not yet been validated in any way in terms of fruit composition and wine sensory attributes, it’s hoped the project will also help to validate the areas.

“So, how is this activity relevant to (growers)?” asked Dr. Reynolds. “Consider this:  we all agree that throughout the region, soil texture and, hence, water-holding capacity, is different. That in itself may be regional and may form a basis for terroir. We also could agree that water stress has become an issue and many growers have either installed irrigation or are considering it. If we are able to find that water stress is a negative determinant of terroir, then that speaks directly to the use of irrigation. If we find that sections of vineyards have better wine quality as a result of water stress or lack thereof, then that speaks to managing of sub-blocks and designation of blocks or sub-blocks based on degree of water stress. Ultimately, terroir gives specificity and provenance to a wine, and that equals value.”

Others involved in the project include Javad Hakimi, Ph.D. student, Brock University; Jim Willwerth, M.Sc. student, Brock University; Dr. Ralph Brown from the School of Engineering, University of Guelph; and Dr. Richard Heck, Land Resource Science, University of Guelph. Dr. Brown and Dr. Heck will be overseeing spectral reflectance data collection and monitoring vines using helium blimps and high-resolution imaging from aircraft. Dr. Heck will also be collecting soil conductivity data.