To make a classic dirty martini, follow these steps:
- Add plenty of ice to a mixing glass.
- Pour in 2 ½ ounces of good London dry gin (or vodka if preferred) and ½ ounce of dry vermouth.
- Add ½ ounce of olive brine (the salty liquid olives are packed in).
- Stir the mixture until very well chilled.
- Strain into a chilled martini glass.
- Garnish with three large olives on a cocktail skewer and serve.
The olive brine is what makes the martini "dirty," and the amount can be adjusted to taste for more or less brininess. Some recipes suggest stirring rather than shaking to keep the cocktail clear and smooth. The garnish of olives complements the savory flavor of the olive brine.