The group - renamed Cains Beer Company PLC - will be 57.65 per cent owned by brothers Sudarghara and Ajmail Dusanj, who bought Cains in 2002.
Sudarghara will be chief executive and Ajmail will be chief operating officer of the new business.
Ajmail said: "It gives us the full, integrated beer business from brewing to selling it, and that will be fantastic."
Sudarghara said: "Our vision for the new group is to become Britain's favourite beer company. This latest deal puts Cains into a new league and will provide an excellent platform for the future growth of the business."
Bank of Scotland provided £40 million for the deal, which is due to complete on June 7, and the Dusanjs have invested £3.5 million.