In this episode of Trellis Talks, Caleb Mosley sits down with soil scientists Dr. Paul Anamosa and Dr. Nick Madden to explore their 2023 paper, “The Other White Rock in Coombsville Vineyards.” The conversation unpacks the geological mystery and viticultural significance of diatomaceous earth found in the Coombsville AVA—a lightweight, silica-rich sediment formed from freshwater algae in an ancient caldera lake. Anamosa and Madden discuss how these unique soils, often mistaken for volcanic ash or bentonite, impact vine growth, emphasizing their low pH, high aluminum toxicity, and unusual water retention characteristics. They explain how proper soil analysis and management—particularly the use of gypsum and lime—are crucial for successful vine development in these challenging conditions.
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The episode also delves into the broader story behind their collaboration, from international development work to building one of Napa’s most extensive soil pit databases. As Paul transitions into retirement, he reflects on the importance of mentorship and passing on deep technical knowledge to the next generation of consultants like Nick and their colleague Scott Nippelmeyer. Their combined efforts promise a new era of viticulture grounded in science, innovation, and deep respect for Napa Valley’s complex terroir.

NVG is working with UC Davis to advance research on wine grape smoke exposure in the aftermath of the Pickett Fire. If you believe your grapes may have been affected, we are urgently requesting vineyard samples to support this important study.

By contributing, you will help enhance air quality modeling and aid in the development of a rapid, cost-effective tool to assess smoke risk. All data will remain confidential, and while results will be shared with participants, they are intended for research purposes only not for guiding immediate harvest or winemaking decisions. 

To participate: 

• Email Arran Rumbaugh and Ben O'Dwyer stating the number of samples you can provide.
• After you receive confirmation, pick up clean 5-gallon bucket(s) in Oakville (7855 St. Helena Highway) between now and Friday, September 26, 2025.
• Collect one 5-gallon bucket of clusters per grape variety (up to two per vineyard), labeling each with variety, date/time of harvest, and vineyard GPS coordinates. Priority varieties: Chardonnay, Sauvignon Blanc, Cabernet Sauvignon, and Zinfandel.
• Drop off samples at the NVG office in Napa (831 Latour Court, Suite A).

This unfortunate fire event gives us a critical chance to build tools that will protect growers for years to come. Thank you for contributing to research that benefits the entire Napa Valley community.
 

In this episode of Grown in Napa Valley, host Caleb Mosley first speaks with Julien Dumercq of IVES (International Viticulture and Enology Society), who highlights the organization’s mission to provide open-access research in viticulture and enology. Julien explains how IVES grew from a small initiative in Bordeaux into a global network of 35 universities and research institutes, supported by members and partners including several Napa Valley wineries. Their peer-reviewed journals, multilingual technical reviews, and international conferences foster collaboration and innovation, ensuring that research is widely available and free from financial barriers. Julien emphasizes the importance of building community across continents, sharing best practices, and maintaining scientific integrity while adapting to new technologies like AI.
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The conversation then turns to the U.S. with Randy Heinzen of Vineyard Professional Services and Donnell Brown of the National Grape Research Alliance (NGRA). Randy shares his journey from Napa to Paso Robles and his experiences farming across diverse sites, underscoring the value of research and cost-based vineyard management. Donnell explains NGRA’s national role in setting research priorities for all grape sectors—wine, juice, table, and raisins—and in advocating for projects with USDA and funding agencies. Together, they stress the importance of collaboration, sustained investment in research, and engaging the next generation of leaders to address challenges such as climate change, pests, and shifting market dynamics. The episode highlights Napa Valley’s role in both global and national research efforts, bridging science and practice to support resilient grape growing.

• “Research should be available for everybody in the world… it’s about freedom.” - Julien Dumercq
• “What we say is correct now becomes the origin of innovation and change—it’s how science shapes the vineyard.” - Julien Dumercq
• “At the end of the day, farmers are really good at solving problems. That resilience is what keeps us going.” - Randy Heinzen
• “You farm to the site—whether it’s two tons on a hillside or seven tons in sandy soils, the goal is making it work.” - Randy Heinzen
• “We’re building a big tent of researchers across the country to solve problems that no single region can face alone.” - Donnell Brown
• “We’re in a period of unprecedented headwinds—climate change, oversupply, shifting consumption—and the only way forward is working together.”​ - Donnell Brown