When 'milkshake' was first mentioned in print in 1885, it was an adult, alcoholic beverage similar to eggnog, containing whiskey and eggs. It wasn't until the early 1900s that it became the wholesome, ice cream-based treat we know today. The turning point was the invention of the electric blender by Steven Poplawski in 1922. Before the blender, milkshakes were shaken by hand, resulting in a much thinner consistency. Walgreens employee Ivar 'Pop' Coulson is credited with adding two scoops of vanilla ice cream to the standard malted milk drink in 1922, creating the 'thick' milkshake. This invention coincided with the rise of the American 'Diner' and 'Soda Fountain' culture, turning the milkshake into a symbol of youth and Americana.