Prompt: Many of you have heard this French word used to describe the influence of soil, topography, location, etc. on wine characteristics. (It is occasionally also used for climatic and winemaking influences as well.) Comment on your experience with this term in your own region and in other wines from around the world. Is there such a thing in most (or all) instances? Do you think it is primarily a marketing tool in the US due to the lack of regulation and diversity in winemaking?
Discussions of terroir can be fraught because it seems to be a term that means something different for each person. My previous experience of the term terroir is the idea of how a particular vineyard site is unique or distinct from other sites, and how that affects the wine. Particularly in the crunchier sides of natural wine and biodynamics, I have observed an association between the character of the soil/site and the actual flavors or textures present in the wine, e.g. chalky soil leading to a perceptible chalky character in the wine.
What's fascinating to me about this association is that it lives in the twilight zone between tradition/empirical observation and academics; that is, it's a strongly held belief by those who have observed it in their own experience, and yet science has yet (as far as I can tell) been unable to describe an actual pathway for those flavors to travel from the soil to our taste buds.
It's interesting to come to this question after a week of reading in-depth academic reviews and textbook chapters about the incredibly varied ways that a vineyard site can contribute to the final quality of a wine. I was struck by each author's careful insertion of a qualification to express that the grape life cycle is so complex that it's almost impossible to account for every possible variable when designing experiments regarding e.g. the effects of soil composition, light, etc. And yet, it's undeniably true that each of these tiny variables can make an impact on the outcome.
So where does that leave us? I have begun to think of it like this: in Computer Science, there's this concept of a hashing algorithm. The idea is that you can come up with a formula that, when given a dataset (like a user profile for example), condenses it all down to a tidy little alphanumeric code that you can then use to reliably look up that information later because it's unique to the data you fed into it.
The analogy I'm going for here is that for each vineyard site, once you combine its individual conditions of soil type/depth/moisture, micro/macroclimates, diurnal shift*, etc - it may well be true that the final hashed result of each combination is unique, because there are simply so many variables that it ends up being highly unlikely that any two vineyards have exactly the same conditions. And that doesn't even include all of the ways that the farmers can then begin to manipulate the conditions themselves.
So, in this way, I suppose I do believe in the concept of terroir when defined as 'vineyard sites each have a unique combination of growing conditions, each condition of which is known to affect the final outcome of the wine.' However, the existence of unique growing conditions and therefore (perhaps) unique grapes does not 100% lead to the outcome of a distinctly unique wine, given all the ways that winemakers can and do intervene with the raw materials.
The question of whether it's a marketing gimmick is a bit of a leading question, but it's a fair one. If your wine is processed within an inch of its life, does it really matter where it's from? Does your wine actually display the effects of the growing conditions if you've put your finger on the scale by acidification or chaptalization**? This line of thinking becomes increasingly slippery as we try to define the types of winemaking decisions that could add to or remove a sense of place from the wine. If you do a saignée***, are you doing so to eliminate a watered-down character that would have represented the terroir, or are you giving the wine a chance to show its true colors by concentrating it down? Etc.
These are questions that I expect to develop stronger opinions on over the course of my learning and of my career, but it feels premature to have strongly held opinions on the subject when I'm just barely starting out. That being said, I do find myself drawn toward lower-intervention styles of winemaking, perhaps in part because the results do tend to be more unique than higher-intervention styles.
* the spread between the highest and lowest daily temperature
** the (usually illegal) addition of sugar to underripe grapes in winemaking
*** bleeding off excess juice after crushing grapes in order to concentrate the flavors