Do I need a cocktail shaker?

Only for cocktails that contain citrus, dairy, egg, or fresh fruit — those need the aeration and harder chill that shaking provides. Stirred cocktails (Martini, Manhattan, Negroni, Old Fashioned) need only a mixing glass and a bar spoon.

A cocktail shaker is essential equipment, but probably not the first thing to buy if you are building a home bar around stirred classics. A Boston shaker (a metal tin and a pint glass, $15) outperforms most cobbler shakers (the three-piece domed variety) and is what professional bartenders use. The mixing glass alternative is a heavy-bottomed pint glass and a long bar spoon — total cost about $10. Drinks that require a shaker: Margarita, Daiquiri, Whiskey Sour, Cosmopolitan, Espresso Martini, Sidecar, Pisco Sour, anything with egg white or cream. Drinks that should never be shaken: Martini, Manhattan, Negroni, Old Fashioned, Boulevardier, Sazerac, Vieux Carré — these are spirit-forward and the dilution profile from stirring is part of the recipe. If you have $30 to spend on equipment, buy a Boston shaker, a Hawthorne strainer, a fine-mesh strainer, a jigger, a mixing glass, and a bar spoon. That's the entire toolkit for 90 percent of classic cocktails.