In 1980, Geoff Merrill and business partner Trevor Stratton established Stratmer Vineyards, parent company of Geoff Merrill, Owens Estate and Mount Hurtle Wines. In the early years, Geoff Merrill wines were crafted at various locations across the South Australian wine regions, including Chateau Reynella and Pirramimma in McLaren Vale, and Peter Lehmann Wines in the Barossa Valley. A modern processing plant was established at McLaren Flat in 1984 in a joint venture with fellow winemaker, Goe DiFabio, which centralised the production of Geoff Merrill wines and allowed greater control over the winemaking process.
Trevor Stratton eventually sold his share of Stratmer Vineyards in 1992 to Alister Purbrick of Chateau Tahbilk, who remained a 50% partner until 2005. Geoff is now the sole owner of the company and continues to develop and produce exceptional wines.