Joseph Phelps Vineyards operates in Napa Valley, where cool coastal influences and well-drained soils support the cultivation of Pinot Noir and Chardonnay. The winery's portfolio centers on these varieties, with Quarter Moon Pinot Noir and the Proem series—including Proem No. 4 Chardonnay and Proem No. 3 Pinot Noir—at the core of its production. These wines have been assessed by major critics including Wine Advocate, Wine Enthusiast, Wine Spectator, and Decanter. The Quarter Moon Pinot Noir demonstrates the region's capacity for structured, age-worthy expressions of the variety, while the Proem bottlings reflect precision in both white and red winemaking. Napa Valley's established reputation for Cabernet Sauvignon notwithstanding, the valley's northern reaches and higher elevations yield compelling Pinot Noir and Chardonnay, varietal expressions that benefit from the area's diurnal temperature swings and extended growing season.