Terroir: What does it mean?
The French have a name for it: "Gout de Terroir" or, more or less, "the taste of the soil;" and the most ardent advocates of this theory argue that the actual flavor of the soil in which the grapes are grown literally communicates itself to the wine. Chablis, by this line of thinking, gains a steely mineral character from the chalky soil of its Burgundian vineyards; the wines of Graves in Bordeaux acquire a "stony" quality from the region's gravelly plain.
Most of us find this a bit extreme, but there's ground for a more serious argument when we expand the definition of "terroir" to incorporate the overall effect on wines of the soil and microclimate in which the grapes are grown. Do Chardonnay grapes grown in Burgundy (for instance) produce wines with a consistent, identifiable character that distinguishes them from the same grapes grown in California, or those in turn from Australian Chardonnay? Does the vineyard matter, whether the grapes in question are grown on the other side of the road or the other side of the world?
This is material from which serious wine fanciers can build extended and joyous debates, and there's little question that the wines of specific regions - especially historic wine regions like Burgundy or Bordeaux - often show recognizable qualities that makes it possible (if not necessarily easy) to pick them out in a "blind" tasting, without the taster being aware of the specific wine being tasted.
But the wine maker's skills, and the decisions made between the grapevine and the bottle, are significant too. Should Chardonnay be aged in oak barrels, which impart strong and characteristic flavors, or in stainless steel, which is neutral? Should the wine maker put the wine through "malolactic fermentation," which reduces the wine's perceived acidity and typically adds rich and buttery flavors? These processes, commonplace in the New World but relatively rare in France, make a significant difference in the nature of the finished wine, but it's not "terroir."