what is the difference between shaken and stirred
Stirring is a more gentle technique for mixing cocktails and is used to delicately combine the drinks with a perfect amount of dilution from the ice. Many gin and whiskey cocktails are stirred because shaking is said to bruise the spirit (though that is also up for debate).
Diluting Effect. Shaking a cocktail in a shiny, silver bullet-shaped vessel creates a mini-exhibition in a bar or at home with friends, making it a popular way to create and serve martinis and Manhattans. If your goal is to make drinks a little less potent, this is the way to go.