Well, I don’t think I could explain terroir any better than the Wiki article you linked to.
Simply put it’s the idea that the soil, sun and water aspects along with the topography (altitude, slope, etc.) of specific areas are responsible for how a wine tastes.
Macroclimate, mesoclimate, and ultimately the microclimate (the area immediately around a vine) are all considered. In Burgundy, vineyards are tightly planted, and tiny portions are sometimes owned by several people (I believe there is one vineyard, 50 hectares in size, with over 80 owners), which I personally think gives them a ‘marketing’ reason to sing the praises of terroir.
That doesn’t mean I don’t believe in it. I do. And I think most vineyard and winery owners do.
For a quality wine, where and how the grapes are grown is vital to the final product. As important if not more so than the winemaking processes that follow. There is a saying I hear often “You can make bad wine with good fruit, but you can’t make good wine with bad fruit.” I definitely believe in this.
California is growing into its own terroir. Actually, most of America is, as well as several other New World growing regions. Russian River Pinot Noir, Napa Valley Cab Sauv, New Zealand Sauv Blanc, Argentinian Malbec - these are all examples of terroir to me, the right grape varietals growing in the right areas/conditions, each one giving the wine a certain trait, a certain ‘something’ that lets you know “This is a New Zealand Sauv Blanc.”
Hope that makes sense.
Anyway, I was also unable to find the Domaine des Nazins, but I did find the same Brouilly flickster did, the 2004 vintage though, of the Chateau de La Chaize by Marquis de Roussy de Sales. I will open it up tonight. I do have a couple of other Cru Beaujolais on the rack, a Moulin-a-Vent, and a Fleurie, I might open them up sometime this weekend for comparison.