In this episode of Trellis Talks, host Caleb Mosley reconnects with phenolics researcher James Campbell, now based in Napa Valley and leading a lab focused on vineyard and wine phenolic analysis. Their conversation explores the science behind phenolic development in wine grapes, from early-stage flavonol formation to anthocyanin synthesis and degradation. James emphasizes the importance of early-season practices—like precise leafing and light management—and shares findings from multi-year studies on the effects of heat and irrigation on phenolic preservation. One key insight is that applying moderate irrigation during mid-ripening heat waves can mitigate anthocyanin loss, but late-season interventions are often too late to make a difference.

The discussion also touches on the nuanced interplay of variety, environment, and stress, noting that different grape cultivars respond uniquely to heat. James shares that Cabernet Sauvignon shows higher resilience compared to varieties like Sangiovese. The episode concludes with a look into James’s new venture, Integrated Phenolics, which offers rapid, in-depth phenolic assays for growers and winemakers. His goal is to equip producers with actionable data to make informed decisions during maceration and fermentation, ultimately supporting the continued excellence of Napa Valley wines in a changing climate.

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