The whiskey sour is a mixed drink containing whiskey (often Bourbon), lemon juice, sugar, and optionally, a dash of egg white. With the egg white, it is sometimes called a Boston Sour. It is shaken and served either straight or over ice.
The traditional garnish is half an orange slice and a maraschino cherry.
A notable variant of the whiskey sour is the Ward 8, which often is based either in Bourbon or rye whiskey, with both lemon and orange juices, and grenadine syrup as the sweetener. The egg white sometimes employed in other whiskey sours is generally not included in this variation.
Information from - http://en.wikipedia.org/wiki/Whiskey_sour
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