Busting terroir myths: The science of soil and wine taste

It’s true that scrub land in Provence does grow wild rosemary and thyme (not so much lavender, or other ingredients in herbes de provence, though). And it’s true that lots of vineyards grow on what was once scrub land. But the perfume of herbes de provence in the air here largely comes from how common these herbs are in gardens all over. Very few vineyards are planted within a quarter of a mile of the nearest rosemary bush and all the ones on rocky soil probably haven’t been anywhere near them. There is a spiciness to Southern Rhone wines that can aptly be described metaphorically as garrigue (I certainly do so), but I truly doubt that it comes from herbs in the soil the vines are growing on.

True.

But more important are eucalyptus leaves and other bits of tree that get harvested with the grapes. Especially so if machine harvested, but even if picked by hand eucalyptus MOG can get entangled in the grape bunches.

I’m talking my own experience talking to people and reading, forum discussions, etc. Material from Ecology Action. Online international tomato-focused community with some of the world’s big players (which spawned the creation of Tomatoville). It’s anecdotal, but I’ve been talking with prominent people for a long time. The knowledge gap worked both ways, btw. For a long time some pretty basic concepts about soil health were always met with crickets with grape growers. In wine, that knowledge is coming here from France. Talking to tomato growers about the importance of soil characteristics in the resulting flavors was met with disbelief. (My own experience showed some varieties hyper-sensitive to soil type, while many others weren’t.)

I didn’t get the impression they were trying to be biodynamic, per se. More that their exploration and experiments took them to the point where they happened to be biodynamic, other than the BS stuff. Their own research, independently looking at traditional practices in various regions lead to that conclusion.

No. It’s drawn into the plant tissue via the waxy cuticle.

Jonathan,

I’m talking about vineyards I’ve walked in Liguria (just east of the French border) and in coastal Sardinia; in both cases the scrub right outside of the vineyard was composed of largely aromatic wild plants. The simplest explanation is surely that the oils from these plants get onto the bunches.

Yup…Paola d’Andrea’s vnyd down in Deming,NM is surrounded by sagebrush & chamisa. Both loft oils into the air
that settles on the grapes, giving many (not all) wines from his vnyd a distinct sagebrush/chamisa aroma.
Tom

Fascinating.

There’s a Guild Somm podcast episode on this very thing that was very informative and covered similar topics. At first I was almost angry at the notion that soil types doesn’t matter but as I thought about it more, it just makes things even more interesting to me. That means it’s not that simple. As Jim pointed out, there IS a difference, and the science as to why there’s a difference isn’t mature enough to really explain it. Over the years I’ve talked to a few biochemical engineers who are in the business and they always comment that while the soil type itself doesn’t ever effect the wine’s flavor/outcome but drives the plant to do different things. Take and abstain from nutrients at different times due to a myriad of reasons.

We need a serious Design of Experiments done on Jim’s cellar!

I cede to your knowledge of Liguria, about which I know nothing. I was speaking about the Southern Rhone.

I cede to your knowledge of Liguria, about which I know nothing. I was speaking about the Southern Rhone, about which most people speak when they refer to the taste of garrigue. It might also be true of the Luberon, where much more forest land still exists, but I am also not an aficionado of Luberon wine…

I suspect this is a lot of people’s first reaction, but it bears stressing that this is not what the article is saying. He’s saying that the way soil is expressed in the wine is much more complicated than just rock → vine → grapes → wine. Soil is important.

Right. And it’s not something you can organize your wine list by, or claim to taste.

It’s unnecessary to get into a debate about biodynamie to point out that folks who practice it have an obsessive concern with and attention to their soil. One of the reasons biodynamie “works” whether or not you believe in it (I’m a skeptic) is because of this. If adherence to the philosophy leads to a soil-obsession, I’m well in favor of it.

Not so sure of that. Again, the volcanic soil based sites in my cellar have a pretty easily identifiable character. The marine soil sites have a very different character. Tasting the difference is really basic. Is that all soil? I don’t think so but at some level the contribution of the soil into the overall expression of the wine in its 3 dimensions is pretty easy to discern.

Jim I believe that. I’ve done it myself in other places and the different sites are quite different. I don’t know how your sites are situated, or whether there are strips of different rock types in the same vineyard, but I don’t know anyone who can say with any certainty, on tasting a wine, that it came from loess or limestone. We’d have to be blind not to see that there are different types of soil in different vineyards, and even that different weeds grow partly depending on the pH and type of soils, but I would venture to say that if one put six or eight bottles in a tasting, all from say, slate or granite soils, it would be unlikely that someone would be able to tell which came from which soil in a blind tasting. People such as you, who are intimately familiar with specific sites, can likely identify specific vineyards. But it’s a gestalt experience, and as you say, the contribution of the soil is hard to single out.

I’d say usually, but not always. Aside from the choices that can mask terroir, the author touches on something else. Soil types are broad categories. For marketing, people will talk about their wines being the desired soil type. Maybe it’s in the mix, but too muddled to show distinctively. Maybe it’s of volcanic origin, but so broken down by time it has very little in common with younger volcanic soils. Iirc, it’s Ian d’Agata who pointed out how common it is for producers to lie about their soil being volcanic, to put it bluntly. It’s what the region is known for, so they feel they have to claim it, despite their wines being great for non-volcanic soil, despite the reality most of the vineyards in the region not being on volcanic soil.

Put another way, I’ve never been wrong when I called a blind wine as coming from volcanic soil. I haven’t made that call all that many times, either. One a few months ago was obviously Italian and volcanic with the nature of its tannin structure and floral aromatic expression. Not Aglianico. Not Sagrantino. Umm… turned out to be Petite Sirah from Manton Valley. But, since it has so little in common with CA PS, I’ll stick with my original guess. It’s a much better guess.

Good stuff Wes! We need to do a tasting. And here’s another thing - whites or reds?

One thing about comparing wines from the same soil type: It’s typical (on the west coast at any rate) for a soil to be ~80% from one type of rock (volcanic, sedimentary, etc), and the remaining % from a mix of others.

Also, it’s common for vineyards to have several different soils (in different locations of the property). In Burgundy (for example), the boundaries between soils is super precise (because the soils moved very very slowly)…enough that you can have grand cru vines in a row, and village vines in the row next to it (Clos Vougeot for example, tho that grand cru row gets never ending grief). One the west coast, the geologic forces moved the soil much much faster, so the soil boundaries are really fuzzy and imprecise.

None of this is a bad thing (imo), but it makes comparing wines of the ‘same’ type of soil somewhat complicated.

In addition to the Decanter article, Guild Somm has an article (in two parts) by Prof Maltman on this same subject…and I think is a better & more complete description of his ideas (I assume because of space limitations in the Decanter article):

Part 1: Part 1: Soil Principles - Soils for Sommeliers - Articles - GuildSomm

Part 2: Part 2: Vineyard Geology - Soils for Sommeliers - Articles - GuildSomm

I don’t recall a white screaming volcanic soil to me. Not saying there can’t be a signature there that I’ve gotten in retrospect, but subtle enough that it hasn’t been something I’ve honed in on. Maybe some skin contact would bring it out more? Maybe we’ll be finding that out ourselves, at some point…

What’s typical of volcanic wines seems to be particularly high acidity and quite often a somewhat piercing yet not unpleasant bitterness I’m tempted to describe as gravelly minerality. Also whites seem to have a tendency to show somewhat smoky character at times - I wonder if these wines have a tendency toward subtle reduction.

The bright acidity and mineral backbone is quite obvious if one tastes side-by-side an Assyrtiko from Santorini and another from mainland Greece. Or a Palomino from Lanzarote and another from mainland Spain.