Question: When to Shake and When to Stir Cocktails
The debate of shaken versus stirred cocktails is hot, especially when talking about the famous Martini. As you're looking through cocktail recipes you'll see some are shaken, some stirred, but is there a theory behind which method to choose? Yes, there is a general rule (as rules go in bartending). There are always exceptions to this rule so it is best to follow a recipe's instructions or, why not, experiment with both.
When to Shake:
Shake cocktails when they include fruit juices, cream liqueurs, simple syrup, sour mix, egg, dairy or any other thick or flavorful mixers. Shaking will create a strained drink with a cloudy, effervescent look at first that will clear up within a few minutes after straining.
When to Stir:
Stir cocktails that use distilled spirits or very light mixers only. Stirring is a more gentle technique for mixing cocktails and is used to delicately combine the drinks with a perfect amount of dilution. Many gin and whiskey cocktails are stirred because shaking is said to "bruise" the spirit.