Flips and eggnog were famous as well, and as Jerry Thomas noted about Eggnog in 1862 “it has a popularity that is cosmopolitan” which is still true today.
The term milkshake's origins can be traced back to the late 19th century, when an 1885 newspaper described the milkshake as a sturdy drink with milk, whiskey, eggs, sugar, and ice. But by the early 1900s, a milkshake had come to mean a drink made with ice cream and chocolate, strawberry, or vanilla syrup.
With the invention of the electric blender in 1922 by Steven Poplawski, milkshakes became even more popular and it wasn’t long before every restaurant was adding a shake to the menu. In 1922 in Chicago, Walgreens employee Ivar “Pop” Coulson added vanilla ice cream to their usual malted milk drink, inventing the first malted milkshake. This new creation boomed in popularity nationwide throughout the 1930s, and milkshakes became staples at malt shops.
Dairy Queen led the way in the fast food category, introducing milkshakes to their menu in 1949.
Milkshake in history