St Mary's Winery is situated on a strip of Terra rossa soil, some fifteen kilometres west of the township of Penola. Originally a grazing property, the poor topsoils working in combination with rich Terra rossa underneath, yield scant quantities of the most powerfully flavoured wine grapes. Exclusively estate grown Cabernet is harvested for the creation of St Mary's House Block, a wine of overall richness and fine palate structure, dense with varietal fruit character and Coonawarra charm, harmoniously integrated after extended ageing.

The exclusive little vineyard is sited on part of a grazing propertry that has been owned and operated by the Mulligan family since 1937. The vines are planted on an elevated area of Terra Rossa soil over limestone. The soils are generally very stony. Some of the more austere parts of the vineyard are virtually pure rock. The vines that have survived on these stony areas produce relatively small tonnages compared to local averages. Small batches of hand picked grapes are fermented in open vats, basket pressed and barrel matured in climate controlled storage before being bottled on premises. Treated to an extended maturation in a selection of American and French oak hogsheads.