A discussion of soil and geology with Earth Sciences professor Alex Maltman, Alsace producers Olivier Humbrecht and Phillipe Blanc and Master Sommelier and former geologist Wayne Belding.
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Here are a few previous feature articles that provide some background on the topic:
Part 1: Soil PrinciplesPart 2: Vineyard Geology
While I agree the correlation between the soil and the flavors in the glass has been over-simplified, doesn't blind tasting show us that there is some flavor derived from rocks in the ground? When label-bias is taken away, we still pick up on a chalkiness in chablis, savennieres, and sancerre - but not in mosel riesling. Clearly the rocks are contributing something to wine's flavor, although in a much more complex way than chalky soil = chalky wine.
@Rick - I've been thinking a lot about the dry extract thing and how it relates to perceived minerality. I tasted my staff on Alsatian Riesling today after listening to the podcast last night and it was an eye-opener. Which flavors were from extract? Which from minerality?
This was an awesome podcast that provokes important ideas and questions. Thank you for putting it together. A few thoughts:
-I kind-of lean towards the University of Bordeaux and Tablas Creek studies (vs. German theory) that calcium carbonate increases soil ph, in turn creating a greater, healthier cat-ion exchange > resulting in a greater perceived wine ‘stuffing’ (via lower wine ph). This theory almost mirrors human physiology and diet wherein the body will naturally regulate its ph slightly basic and reminds me of the controversy about the dangers of acidic diets… a wasteland for certain pathogens. Trends preach ‘Drink tap water (more basic), not purified water (more acidic).’
-Focusing on how water ph and soil ph affect mineral-like flavor, I wonder how rainfall ph varies globally as well as how water ph changes once it hits rock and permeates soil. In addition, can we infer that irrigated vineyards (more water at an altered ph) lack mineral-like flavor? Is the combination of dry-farming, soils rich with calcium carbonate, and higher rainfall ph win? -AA
My hypothesis revolves around petrichor, which was touched on briefly. If grapes are exposed to wildfire smoke, it can show up in the wine. If grapes are planted near eucalyptus trees, it always shows in the wine. So, the flora of any one region are constantly shedding waxes and lipids, and when wetted on stones, there is a characteristic smell we associate with the smell of stones, when it is in fact the smell of these wetted deposits. Obviously, this is also getting deposited through the air on to fruit, and is undoubtedly ending up in wine. It's a delicate smell, easily masked by higher alcohol, oak, and possibly even fruit. It varies from region to region because the flora varies.
If an austere, high-acid wine reminds one of minerals or seems to have a high "minerality" is that because that wine has a high dry-extract?
What is dry extract? I suspect it's mostly tartaric acid/cream of tartar and a pinhead worth of metals and salts. But it is something that German winemakers are proud to boast of. Why is dry extract measured? What does it signify?
If a wine has a high dry extract, can you taste it or sense it? Is it "minerality?"
Port Ewen, NY
Another great Podcast - very cool to get four experts from three countries all in the same discussion.
However, I think the people bashing the recent wine descriptor "minerality" should relax.
No one ever said they could taste minerals in wine, or dried strawberries, or nutmeg, or tar.
They just use those words to say what they the wine reminds them of.
It's not easy to describe what your tasting or smelling. What does a tomato taste like? What does a pine forest smell like?