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A long vodka is a vodka-based cocktail, popular throughout Scotland and known to be served in some parts of England.
Video Long vodka
Preparation
A long vodka is made by adding lemonade, or soda water, and lime cordial to 1 or 2 shots of vodka on ice. The glass can either be rinsed (and then emptied) with Angostura bitters, or 2-3 drops can be added to taste; distinguishing the drink from a vodka lime and lemonade.
Source of article : Wikipedia