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October 1, 2025 52 mins

How much of what we perceive about the taste of wine is actually shaped by psychology? Are vineyard soils important contributors to a wine’s tasting profile? Why do so many wine producers highlight their soils as a unique factor that makes their wines stand out? Where do the “minerals” we taste in wine originate from?

In this episode of the Unreserved Wine Talk podcast, I'm chatting with Dr. Alex Maltman, author of the new book Taste the Limestone, Smell the Slate: A Geologist Wanders Through the World of Wine.

You can find the wines we discussed at https://www.nataliemaclean.com/winepicks

 

Giveaway

Two of you are going to win a copy of Alex Maltman's terrific book, Taste the Limestone, Smell the Slate. A Geologist Wanders Through the World of Wine. To qualify, all you have to do is email me at natalie@nataliemaclean.com and let me know that you’ve posted a review of the podcast. I’ll choose two people randomly from those who contact me. Good luck!

 

Highlights

What did a Dutch research study show about identifying soil type through blind tasting?

Is there any geological evidence to support volcanic soils imparting certain characteristics to wine?

Why can vines access nutrients from soil but not larger rock layers?

Should we consider the root stocks of vines and the type of yeast used for fermentation when analyzing the taste profile of a wine?

How does consumer psychology influence our perception of the taste of wine?

Which aspects of geology and wine is Alex planning to write about in the future?

If Alex could share a bottle of wine with anyone outside the wine world, who would that be?

 

Key Takeaways

How much of what we perceive about the taste of wine is actually shaped by psychology?  It's the psychology that people think, “Oh, heavy bottle. This must be a classy wine.” For many wine drinkers, what the wine expert says will override the more academic factors, rather like a clinician saying, take these tablets, you'll be better, if the wine authority says you're going to taste vanilla. Yeah, I'm getting vanilla.

Are vineyard soils important contributors to a wine’s tasting profile? In one experiment, several growers planted four different grape varieties, each in different soils, and then tried to grow the grapes, vinify the grapes uniformly, and then sent the finished wines off to a completely independent expert tasting panel. The panelists were only able to group the wines according to variety. Soils didn't come through at all.

 

For wine producers, soil is one of the only factors that are difficult to replicate, so they're going to say their soil is special. It's a great selling point.

When some wine commentators are saying they're tasting minerals from the soil because it's been taken up by the vine root and transmitted through to the wine. Well, no, that doesn't happen like that. But in any case, any nutrients that were taken up by the vine root and did make it all the way through to the finished wine, almost certainly, in practice, will have originated in the humus.

 

About Dr. Alex Maltman

Alex Maltman is Emeritus Professor of Earth Sciences at Aberystwyth University, in Wales, U.K. Alongside a decorated career in university teaching and research, Alex has for fifty years grown vines and made wine at his home. And through this, perhaps inevitably, he became interested in vineyard geology and its fashionable but poorly understood relationship with wine. This led to numerous publications in both the popular press and academic journals. Alex is the author of the acclaimed Vineyards, Rocks, and Soils: A Wine Lover’s Guide to Geology and newly released Taste the Limestone, Smell the Slate. A Geologist Wanders Through the World of Wine.

 

 

To learn more, visit https://www.


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