Margerum produces wines from Santa Barbara County's Central Coast terroir, where cool maritime influence shapes the character of Mediterranean and Rhône varieties. The Estate Block Three Vineyard Syrah, rated 93.3 by prestige critics, demonstrates the region's capacity for structured, age-worthy reds. The winery's Cinsault (93.0) and M5 Reserve blend (92.4)—a complex mix of Mourvèdre, Syrah, Counoise, Grenache, and Cinsaut—reflect a focus on southern French and Spanish grape varieties adapted to California's conditions. Wine Enthusiast, Wine Advocate, and Wine Spectator have assessed the portfolio. The wines balance the ripe fruit typical of the Central Coast with the mineral precision and acidity that Santa Barbara's coastal climate imparts.