When garnishing a cocktail, what is the most common garnish for a martini?

The most common garnish for a martini is an olive or a lemon twist. This choice reflects traditional cocktail culture where olives, particularly green olives, are favored for their briny flavor that complements the dry characteristics of the gin or vodka typically used in a martini. Additionally, a lemon twist provides a burst of citrus aroma, enhancing the drink's overall taste and sensory experience.

The olive serves not only as a garnish but also has become synonymous with the martini itself—a symbol of sophistication and elegance. The use of a lemon twist offers a refreshing contrast, adding complexity to the drink's profile.

Other garnishes such as a cherry, cucumber slice, or sprig of mint do not align with the traditional presentation of a martini. Cherries are more common in sweeter cocktails like Manhattans or on tropical drinks, while cucumber slices and mint sprigs are often associated with lighter, refreshing cocktails rather than the classic flavor profile of a martini. Thus, the choice of an olive or lemon twist is integral to the identity of the martini.