Which glass for which drink? A fit checker for coupe, rocks, highball and Collins

A glass is not just decoration. Its size decides how full a drink looks, how long it stays cold, and whether you can carry it across the room without a spill. Pour a 90 ml Daiquiri into a 400 ml tumbler and it looks lost; pour a 200 ml Gin and Tonic into a 180 ml coupe and it is on the table. This piece gives you a quick way to check a glass before you pour.

The fit checker

Pick a drink, pick a glass, and choose the ice. The checker adds up the liquid, adds the water the drink picks up while it is shaken or stirred, adds the ice that takes up room, and shows how full the glass ends up. Every glass has a typed size you can change: pour water from a measuring jug into your own glass up to the brim and type the number in.

How the numbers work

Three rules sit behind the checker, and you can use them without it.

Water is an ingredient. Ice melts into a drink while you shake or stir it, and that water is part of the recipe. Shaking adds about 20 to 25 percent water to the overall cocktail, and stirring about 15 to 20 percent, according to the bartenders at Death & Co. The checker uses 22 percent for shaken and 17 percent for stirred drinks. A 90 ml Daiquiri recipe therefore ends up around 110 ml in the glass.

Ice takes up room. A big cube is solid, so it displaces its own volume; the checker uses about 90 ml for one large cube. Cubes packed into a glass leave air gaps that the drink fills, so roughly half of the space they take up is actual ice. That is a rule of thumb, not a measurement, but it is close enough to choose a glass.

Glass sizes vary. Difford's Guide lists a coupe at about 200 ml, a Nick and Nora at 170 to 180 ml, a rocks glass at 270 to 320 ml, a highball at 180 to 300 ml and a Collins at 350 to 410 ml, all measured to the brim. Real glasses range widely around those, so measure yours once and write the number on the base with a marker.

Fill to about nine-tenths, not to the brim. The dashed line in the picture is that mark.

Why size matters

For drinks served up, with no ice in the glass, size is about temperature. A shaken or stirred drink leaves the shaker as cold as it will ever be, and then it starts warming. A wide, shallow coupe has a big surface and warms quickly. Difford's advises keeping a martini glass to 7 oz (200 ml) so the drink does not warm up before you finish it, and a Nick and Nora, which is narrower and deeper, is a good swap for any coupe drink. Chilling the glass first helps, too.

For long drinks over ice, size is about the ice. The ice keeps the drink cold, so you want enough of it that the glass is mostly full of ice and drink. In a glass that is too big, the same drink sits low, the ice floats on top and the fizz escapes across a wide surface. Difford's calls 8 oz (about 235 ml) the ideal highball; a 200 ml Gin and Tonic with a full glass of ice needs a bigger highball or a Collins glass, and the checker shows that at a glance.

Which glass for which drink

The same glass can serve alcohol-free drinks: a lime and soda belongs in the same tall glass as a Gin and Tonic, and it should look just as good. Keep the pour measured, too. A bigger glass invites a bigger pour, and the point of a spec is that the drink is the size you meant. Difford's calls a full 2 oz of spirit in a highball a generous serve. Drink responsibly, and never drive after drinking.

What to look for in a glass

At any budget, four things matter more than the shape. First, know the brim capacity: if the seller does not state it, measure it yourself. Second, a thin rim feels better to drink from and a heavy base keeps tall glasses stable. Third, check that it is dishwasher safe if you will wash it often, since fine stems break in the rack. Fourth, buy a few of one good size instead of a mixed set; two coupes, two rocks glasses and two highballs cover most drinks in this piece.