The Vodka Sour is the sour formula with the training wheels off — no barrel notes, no botanicals, nothing between you and the ratio. Vodka's neutrality means the lemon, the sugar, and (if you're doing it properly) the egg-white foam are the drink. That makes it the least forgiving member of the sour family and, when it's dialed in, one of the cleanest: bright, silky, and cold as a first impression.
With nothing to hide behind, a sour has to be built straight — this is the drink that grades your ratio.
History
The sour is one of the founding templates of American drinking — spirit, citrus, sugar — codified in print by the 1860s. The vodka edition is much younger, arriving with vodka's mid-twentieth-century conquest of the American back bar, and no individual creator is documented; it's a formula application, not an invention. It shares the family tree with the Whiskey Sour above it and the Lemon Drop beside it.
The Spec
The house sour ratio: two parts spirit, three-quarters sour, three-quarters sweet, plus an egg white for texture. Serve it up in a coupe with the foam intact, or over ice if you're skipping the white.
The Egg White Question
One egg white, dry-shaken first (no ice) to build the foam, then shaken again with ice to chill. It adds no flavor — only that dense, meringue-soft cap that makes the drink feel finished. Aquafaba (1 oz) substitutes cleanly for the egg-averse.
Fresh Lemon, Always
Vodka won't cover for bottled juice the way a barrel-aged spirit might. Squeeze the lemon the same hour you drink it; this recipe has exactly one aromatic ingredient and that's it.
Bottom Line
The Vodka Sour is the sour reduced to arithmetic, and good arithmetic is satisfying. Master it and every other sour on this site becomes a variation you already know.