The brewery was founded in 1984, by Ed McNally, who was disappointed in the beer available to buy in
Calgary, AB. A lawyer by trade, McNally was representing a group of barley growers in a legal action against the Alberta Wheat Board in the 1980s. Through the course of the legal action, McNally learned that the Alberta climate produces 2-row barley that is ideally suited for malting, and had access to glacial water from the nearby Rocky Mountains. At the time, most barley production in Alberta was used as cattle feed. With an entrepreneurial background, McNally decided to open a craft brewery. The name "
Big Rock" was chosen after the
Okotoks Erratic, a 16,500-tonne glacial boulder located outside of the town of
Okotoks. The first
brewmaster was Bernd Pieper, a German brewmaster for
Heineken International. In Summer 1986, when Big Rock had been in production for only a year, workers at the
Molson and
Labatt breweries went on strike. This proved to be a windfall for Big Rock, as it was the only beer available in Alberta that summer, and production quickly grew. The second brewmaster was Larry Kerwin, a former brewmaster for Molson and current distiller at Eau Claire Distillery. Kerwin started as a brewer at Big Rock under Pieper in 1994, and took over as brewmaster in 2003 when Pieper retired. He was with Big Rock for 12 years. The third brewmaster was Paul Gautreau. Gautreau joined Big Rock in 1986 as its fourth employee and worked in marketing and operational capacities before replacing Kerwin as brewmaster. Gautreau is a graduate of the Brewing and Packaging program at the
University of California, Davis, the Brewing & Malting Science program at the
University of Wisconsin–Madison, and the
Institute of Brewing and Distilling in London, England. He is also a member of the
American Society of Brewing Chemists, the Institute of Brewing and Distilling, and he has served as president of the
Master Brewers Association of the Americas. The fourth brewmaster was Ignacio Rodriguez, who held the role from 2022 to 2025. He had previously worked for Molson Coors, Bridge Brewing Company, and Craft Collective Beerworks. McNally retired from day-to-day operation of the company, retaining the ceremonial title "Chairman Emeritus" until his death in August 2014. In March 2015, Big Rock's Urban Brewery opened in
Vancouver, British Columbia. In 2017, Big Rock partnered with restaurateurs
Oliver & Bonacini to open Liberty Commons at Big Rock Brewery, located in
Liberty Village,
Toronto. These locations later closed in 2024 and 2025, respectively, as Big Rock focused on their Calgary location. On July 23, 2018, Big Rock closed an amended transaction to acquire certain brewing assets and inventory related to branded beer and cider from the Fireweed Brewing Corporation, including beverage brands such as Tree Brewing, Dukes Cider, and
Shaftebury. ==Products==