The Pisco Sour is made with bitters, sugar, lime juice, egg whites & Pisco, this pale grape spirit
[DOC] [TLE] Pisco Sour cocktail [PAR] ... lay claim to the origins of the Pisco Sour and indeed the spirit it is made from ... 
My Peruvian friends favour pisco made from the Quebranta grape or even ... 
Convention has it that the Pisco Sour is garnished with three drops of bitters .... "
egg white, a cup of pisco, a teaspoon of sugar and a few drops of lime juice to 
taste".