Through stress comes concentration. Neighboring May Rock (the largest outcropping of quartz along the Mother Load) provides an example of Casto estate's unique soil profile. Layers of rich red clay held together with tiers of shale and quartz create somewhat of a maze for the root structure of our 25 year old Zinfandel vines. Taking five to ten years for roots to completely mature in some instances, the Casto estate vineyard profile tends to crop a meager one and a half tons per acre. We find this drives the minerality, fruit, and color concentrations through the roof in all of our estate wines.