Shaken or stirred, and how to know when to pick each one.

Stir when every ingredient in the drink is already clear — spirits, vermouth, fortified wine, and nothing else. Think a Martini, a Manhattan, a Negroni: there’s no juice or cream to blend in, so all the drink needs is to get cold and pick up a little water. Thirty seconds with ice in a mixing glass brings the drink to the right temperature and keeps it perfectly clear — a good Martini feels silky because there’s no air in it. Shake the same drink and you’d cloud it up and water it down too fast. (The old line about shaking “bruising” the gin is a myth — it doesn’t bruise anything; it just adds air and water — but the cloudiness is real, and on an all-spirits drink it just looks like a mistake.)

Examples: Dry Martini, Manhattan, Negroni, Boulevardier, Martinez. The famous exception proves the rule: Bond’s Vesper is all gin, vodka and Lillet, a textbook stir, but he orders it shaken — and it comes out cloudy, ice-cold and a little watery. That’s not some secret upgrade. It’s the rule broken on purpose, and you can taste it.

The rule: if you can see through everything in the glass, you stir it.

Shake when a drink has something in it that isn’t a clear spirit or wine — fresh citrus, juice, egg white, cream. Now there’s a second job on top of getting the drink cold: those ingredients need to be beaten together and frothed up, and only a hard shake with ice will get the job done. You can see it work — the foam on a whiskey sour, the thick crema on an espresso martini, the cloudy paleness of a daiquiri. That’s air, shaken in. Ten to fifteen seconds, hard, then strain. A drink with pulp or fruit shards usually gets a second pass through a fine strainer; one made with egg white gets a dry shake first — no ice, just to build the foam — then a second shake with ice to cool it down.

Examples: Daiquiri, Margarita, Whiskey Sour, Sidecar, Espresso Martini, and the egg-white Clover Club.

The rule: if anything in the glass is cloudy, you shake it.

Some drinks never need a shaker or a mixing glass at all — you make them right in the glass they’re served in. This is where highballs live: a spirit and a long mixer poured over ice, stirred once, done. It’s where the on-the-rocks drinks live too, the ones where a single big cube does the slow watering-down an Old Fashioned needs. And it’s where muddled drinks live — a Mojito, a Caipirinha, a Mint Julep — built right where you crush them, since there’s nothing to gain by moving them. Building transfers the effort from the bartender to the ice; over a long, slow drink, the ice does the real work.

Examples: Old Fashioned, Mojito, Caipirinha, Americano, Mint Julep, Dark ’n’ Stormy.

The rule: if you don’t strain it, you build it in the glass.

The last two methods are a smaller tropical niche, and they come down to one thing: texture. Blending — the Piña Colada, the Zombie, Don’s Special Daiquiri — chops ice right into the drink until it’s a smooth, frozen slush; the blender isn’t really mixing, it’s making the ice part of the drink. Swizzling — here, just the Chartreuse Swizzle — means packing a glass with crushed ice and spinning a swizzle stick between your palms until the outside of the glass frosts over. Both come from tiki, and both are targeting the same thing: when the cold, slushy texture is the whole point, you start with crushed ice.

Examples: Piña Colada, Zombie, and the Chartreuse Swizzle.

The rule: when the texture is the drink, you crush the ice.