The gin sour is a classic cocktail made with gin, lemon juice, and sugar that predates Prohibition in the United States. Adding club soda water to the mix turns it into a gin fizz.
The egg white is optional but adds a beautiful layer of foamy texture atop the drink, which you can then decorate with bitters. Usually 2-3 drops of Angostura bitters. This sour is light, refreshing, and with a lot of character, one of the original cocktails of its kind appreciated in a similar manner since the late 1800s.
Gather the ingredients.
In a cocktail shaker, pour the gin, lemon juice, simple syrup, egg white, if using, and bitters.
Dry shake the cocktail without ice.
Fill the shaker with ice and shake.
Strain into an old-fashioned glass.