A classic martini can be made with either gin or vodka, but when it comes to a chocolate martini, a sweet dessert-like variation, vodka is your best bet. The chocolate martini is a more specific drink in another way, as well — while a basic martini can be shaken or stirred, you should not stir a chocolate martini and be done with it.

Chocolate martinis often use chocolate syrup, which is heavier than other liquids and will settle at the bottom of the glass if all you do is stir the drink together. When a chocolate martini is shaken, not only is the chocolate perfectly blended with the other ingredients, but the whole drink chills thoroughly for an ice cream-like effect.

When you shake a martini, you also add air to the drink, which makes for a foamy and delicate sensation on the tongue. If you are ever in doubt about when to shake a cocktail and when not to, Bon Appétit says that when you mix nonalcoholic ingredients with alcoholic ingredients, you always want to shake your martini.