Stirred, not Shaken.
The number one rule in spectacular Manhattan making is, the drink must be stirred rather than shake. In fact, all cocktails with clear liquid should be stirred. Stirring your Manhattan will bring the temperature of the drink down without disturbing the texture or clarity of the cocktail. Manhattans are intended to be smooth, almost silky. When you shake a Manhattan, it adds tiny air bubbles to the liquid, which change the texture of the drink and create a swamp like layer. Our suggestion, stir your Manhattan for 15 to 20 seconds before straining it into a cold cocktail glass.