The History of the Biergarten
In the then Kingdom of Bavaria in the 19th century, seasonal limitations on when beer could be brewed were already in the Bavarian brewing regulations by 1539; in 1553, Albert V decreed a period from 29 September, the feast of St. Michael, to 23 April, the feast of Saint George, for its production. The cool seasons were chosen to minimize the risk of fire when boiling mashed grain into wort. Numerous conflagrations had occurred, resulting in the prohibition of brewing during the summer months. In response, large breweries dug cellars in the banks of the River Isar to keep their beer cool during storage. "Beer cellars" for consuming beer on premises naturally followed.
To further reduce the cellar temperature during the warm seasons, 19th century brewers covered the river banks with gravel and planted chestnut trees for their dense spreading canopies. Soon after that, serving cool beer in a pleasant shaded setting emerged. Simple tables and benches were set up among the trees, creating the popular "beer garden" we know today. Food service followed, aggrieving smaller breweries that found it difficult to compete. They petitioned Maximilian I to forbid it. In compromise, beer gardens allowed their patrons to bring their own food, still common practice. As a rule of thumb, beer gardens offer clothed tablesets, whose guests must buy food from the house. If you bring your own food, you must use the bare table sets. With the advent of widespread lagering in the later 19th century, beer gardens grew more popular than ever.
Photo to right Decree by King Maximilian I, Joseph von Bayern, dated January 4, 1812, allowing Munich brewers to serve beer from their cooling cellars, but no food other than bread