Some aspects are explainable, e.g. limestone-rich soil increases the acidity of grapes, which can impart notes of citrus on the wine. But what about notes of chocolate, or berries, or stone fruit? In some cases, this is totally because the winemaker actually conditions with those things, but in plenty of cases, this is actually imparted by the growing conditions.
For what it's worth, the impression I get is that Americans place a lot of stock in the varietal of grape, e.g. Pinot noir or Chardonnay, whereas the French place a lot more emphasis in the region, e.g. Bordeaux or Burgundy. Both impart different qualities (e.g. it's going to be a lot easier to find notes of pepper in a Tempranillo than in a Chardonnay).
Not going to get into terroir other than to say that to reduce it solely to the soil type is the wrong way to look at it. It’s more of a holistic view of the entire growing microclimate, including soil, topography, water table, general climate conditions, etc.
I’m a sommelier and own a wine shop, for what it’s worth.
Well said.
We're agreed on that front. My comment about limestone was to present one scientific aspect of terroir as _I_ understand it (which is to say, as a casual wine drinker recalling something I'd heard from a winemaker some years back).
That's a fair point about a lot of varietals being very heavily coupled to places of origin, and that's especially true for the big names that we've been discussing. But a white wine from the Alsace region (for instance!) could be a Gewurztraminer, or a Riesling, or something else entirely. (That said, I wouldn't expect an Alsatian white to be an Italian varietal...)
(https://winefolly.com/deep-dive/alsace-wine-region/ suggests a pretty even split between 4 different main varietals, with a tail.)