How Geology Shapes Wine: A Conversation with Terroir Specialist Brenna Quigley

In this episode of the Vint Wine Podcast, host Billy Galanko sits down with Brenna Quigley, geologist and terroir specialist, to explore how what lies beneath the vines shapes what’s in your glass. Brenna shares her path from UC Santa Barbara to working with mentors like Raj Parr and Seth Kunin, and with producers such as Quintessa, Flowers, and Hirsch. She explains how geology helps wineries understand vineyard character, canopy choices, and grape health. Together they discuss what terroir really means, the ongoing debate around “minerality,” and how soil chemistry, pH, and rock type, from limestone to volcanic, affect the style and texture of wine. Key Topics: • How geology shapes terroir, vine health, and flavor across regions • Minerality vs. salinity and why these terms are often misunderstood • Limestone, clay, granite, and volcanic soils and their impact on wine structure and acidity • Vineyard mapping, soil pits, and auger cores in guiding farming and blending decisions Chapters: 00:00 Introduction to the Vent Wine Podcast 00:23 Meet Brenna Quigley: Geologist and Terroir Specialist 04:12 Starting the Interview with Brenna Quigley 04:45 Brenna"s Early Career and Experiences 13:13 Current Vineyard Projects and Techniques 27:29 Comparing Limestone and Diatomaceous Earth 28:10 Geologic Analogies and Misconceptions 28:39 Differences Between Chalk and Limestone 33:31 Understanding Minerality in Wine 37:32 Volcanic Wines and Minerality 40:02 Adapting Vineyards to Soil Types 44:21 Geologic Mapping in Monterey County 45:56 Soil Differences in Wine Regions 48:59 Exciting Vineyard Projects and Podcast The Vint Wine Podcast is hosted and produced by Billy Galanko. For more content follow Billy on Instagram @BillyGalanko_wine_nerd and for partnerships and collaborations please email billy@sommeliermedia.com. Cheers!