Minerality: mythos & reality - What do yo

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SB Ranch

Senior Member
Jun 12, 2007
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<H3 =post-title>Mineral notes in your wine - minerality, if you will - what causes it? Classic viticulture states plainly that it's due to the soil type your vineyard is situated upon. But is that true?

Mineral content of the soil is largely inconsequential to perceptions of 'minerality' in the finished wine. Take the variations in mineral content in Sonoma and Mendocino Counties for calcium (Ca)[8~23 ppm], potassium (K)[1~3 ppm], and magnesium (Mg)[1.5~16 ppm] from vine growing areas. At first we see what looks to be a rather large range of these minerals, but when looked at on larger scales aren’t very significant at all...

That calcium range, the largest of the 3 minerals mentioned, is just 0.008 g to 0.023 grams per kilogram of soil...which really isn't much variation at all, as well as being very low levels initially. How can such a small range for that mineral be responsible for such a large variation in the resulting wines? - the grapevines would have to be phenomenally responsive to those minerals, as would our taste buds (neither of which is the case).

Couple that fact with what has to be a very inefficient translocation mechanism of the minerals into the fruit, and you have even lower variation in the fruit than you do in the soil to start with. Also on point is that there are similar soil compositions in areas of Sonoma and Mendocino Counties which produce such different finished wines, in regards to minerality, that it leads one away from the (romantic) notion of soil as the defining factor in the finished character of a wine. This again is one of the reasons I feel that appellations based on prevailing climate are more important (read 'accurate') than those based predominantly on soil types (Tom, please forgive my love of the 'Sonoma Coast' appellation!).

Historically soil was linked to blood lines, nobility, ancestry &amp; heredity, etc., and it was an easy extension to apply those ideas to wines as well...even though only anecdotal reasons were available to do so. (Witness the use of the term "Noble" varietals when discussing grapevines...more popular vines were thought to have better qualities, more 'pure' and 'noble' in nature than the 'coarse' 'common' varietals...)

The following is from Jamie Goode's Wineanorak [2003 Harper's article] regarding the 'minerality' of the soil being deposited into the fruit:

...Scientific views of terroir
While in some circles it is quite common to hear such literalist explanations of terroir, they are treated with a degree of incredulity by many new world viticulturalists. I asked viticultural guru Dr Richard Smart what he thought of popular notions of terroir which propose direct translocation of flavour molecules from the soil to the grapes, and hence the wine [which is exactly what would have to happen for the 'minerality' of the soil to be tasted].
‘This is an absolute nonsense’, he replied. ‘I have never heard this, yet you say it is popular. Who on earth postulated this?’
[Damn, that quote just kills it! Think back again to the romantic notions of land and 'nobility'...hmmmmm, where could that idea have come from?]

Dawid Saayman, a South African viticultural expert known for his work on terroir, adds that, ‘I don’t believe that the minerals taken up by the vine can register as minerality in the wines. Minerality appears to me to be more the result of absence of fruitiness.’ But it’s pretty much a given that wines that [are] made from grapes differing only in the soil in which they were grown taste different.
[True, but what's not 'a given' is that those differences are soil derived...too many variables are involved for a fermentation to be reduced to just a difference in the soil...and this ignores the fact that if one splits those grapes harvested from a single block, picked on the same day, by the same people, and fermented by the same winemaker &amp; crew into two tanks right next to each other, that more often than not they have somle differences between them...how can that be? Why aren't they the same? They were grown on identical soil under identical conditions, no? Also I think that minerality is not necessarily due to the 'abscence of fruitiness', but rather it's a subtle effect which is sometimes swamped by wines with more apparent fruit aroma...and is therefore easier to detect in less 'fruity' wines.]

So just what is the scientific explanation for these terroir effects? It is an important question, because providing a sound scientific footing for terroir is a worthy cause. Not only will it lend credibility to the concept in the eyes of sceptics [sic], but it will also help the already converted understand and therefore better utlilize [sic] terroir effects....

I just can't see the argument for soils affecting 'minerality' as a plausible explanation.
And unfortunately for terroiristas everywhere, if the soil portion of the terroir argument falls, then so a good portion of the foundation of the current definiton of what terroir even IS is weakened nearly to failure...</H3>
Good article SBR, thanks for sharing. It seems that everything that we have known about wine making is controversial.

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