This recipe for homemade sour mix uses lemon juice with an egg white for texture.
1 cup superfine sugar
1 egg white
2 cups water
2 cups lemon juice, preferably freshly squeezed
Whisk egg white in a medium-sized bowl until frothy.
Stir in the sugar and water or simple syrup.
Add the lemon juice, and stir all ingredients well.
Store the mix refrigerated, and use within 3 days of making it.