Cassels died on Saturday, according to posts on Cassels Brewing's social media pages.
He invested in the brewery after the 2011 earthquake, and after 100 days their structurally sound but broken brewery was reborn to include a bar, café, music venue and restaurant.
Now, they export to the United Kingdom, United States and China.
Cassels also bought the Tannery in Woolston in 1994, and opened a boutique shopping mall.
Christchurch Mayor Lianne Dalziel is remembering Cassels as extremely kind and generous.
She said he created a "real legacy" with the outstanding redevelopment of the Tannery and he was always willing to reach out and support the community.
Christchurch councillor Yani Johanson said his thoughts are with Cassels' family.
He said it is the loss of a local legend, who, after the earthquake, was synonymous with getting people back into the central city.
In 2021, Cassels Brewing Company took out the top spot for American Pale Ale (APA) in the World Beer Awards.
It followed consecutive wins at the awards (2019-20) with a milk stout, beating Guinness and other famous brands.
