Jürgen Winterberg knows about these things.
He runs the meticulously researched bier-in-mainz.de website and has the history of the 78 breweries which have lived and died in and around Mainz.
This is the door surround of what was originally the Brey´sche Aktienbrauerei on the Kästrich (dating back to 1859 and named after Ludwig Brey, the owner of the Löwenbräu brewery in Munich, who – in exchange for the shout-out plus some folding stuff – provided the shareholders with expertise and one of his head brewers) and in 1872 rebranded as the Mainzer Actien Bierbrauerei, at the time the biggest brewery in the country
Things went swimmingly until the Great Depression and world war 2 raised their ugly heads and when production recommenced in 1948, it was at a mere 10% of post-ww1 levels.
Production was up to 200,000 hectolitres in the 1970s, by which time it had been taken over by the Binding brewery of Frankfurt and Dr. Oetker, a baking powder and cake mix manufacturer, who then closed it down in 1982.
Leaving us with 2 microbreweries.