Mitchell's largest vineyard is located at Watervale, several kilometres south of the estate wineworks. Set on the exposed eastern slopes of undulating hills, with long rows of vine, this can be a very bleak place in the middle of winter at pruning time. The isolation and chills has led to it becoming known among the vineyard workers as Alcatraz, a place to do penance in the cold, wind and rain of a Clare Valley winter. Alcatraz, which only ever yields around two ton per acre, is particularly well suited to Riesling, infusing the fruit with great depth of flavour. The fully mature vines are planted to soils that are rich red brown loam and clay over limestone, at an altitude between 300 and 400 metres.