Whiskey Sour vs Pisco Sour: Egg-White Sours Compared

Order a Pisco Sour and you get a cold, tart, foam-capped drink with dots of bitters on top. Order a Boston Sour — the Whiskey Sour with egg white — and you get something that looks almost the same. The two are the egg-white branch of the sour family, built on the same template of spirit, citrus, sugar and foam. What separates them is the spirit: American rye or bourbon in one, Peruvian grape brandy in the other.

This is the Whiskey Sour vs Pisco Sour comparison: the builds side by side, how they taste, which is stronger, where each comes from, and which to make tonight. The Whiskey Sour side follows the rye Whiskey Sour recipe; the Pisco Sour spec is the IBA's official recipe, used as a reference rather than a RyeCentral build.

The Short Version

• Same template: spirit, citrus and sugar, shaken hard with egg white. The Pisco Sour is the same sour template on grape brandy, with egg white standard.
• Whiskey Sour: 2 oz rye, ¾ oz fresh lemon, ¾ oz 1:1 simple syrup; egg white optional (with it, PUNCH and Difford's call the drink a Boston Sour). Up or over ice.
• Pisco Sour (IBA): 60 ml pisco, 30 ml fresh lemon juice, 20 ml simple syrup, one raw whole egg white; shaken, strained into a chilled goblet, dashes of Amargo bitters on top.
• The key differences: grape brandy instead of grain whiskey; egg white required rather than optional; more lemon relative to sugar; and bitters that belong to the recipe rather than to a modern garnish habit.
• Strength: close. Both pour about 2 oz of spirit into a similar volume of citrus, syrup and egg; the spirit's proof decides the difference.
• Order the Whiskey Sour for spice and oak under the foam; order the Pisco Sour for a lighter, floral, more aromatic drink.

Side-by-Side: Build at a Glance

On paper the Pisco Sour's proportions — 2 : 1 : ⅔ — sit closer to Difford's preferred Whiskey Sour formula (2 oz whiskey, 1 oz lemon, ⅔ oz rich syrup) than to PUNCH's 2 : ¾ : ¾. Pisco's lighter, fruitier body wants a little more acid to keep it sharp.

Both Recipes, Side by Side

The Whiskey Sour (Boston Sour with egg white)

1. Add 2 oz straight rye, ¾ oz fresh lemon juice, ¾ oz 1:1 simple syrup and ½ oz pasteurized egg white to a shaker.
2. Shake with ice first, strain back into the tin, discard the ice and shake again without it (reverse dry shake) — or dry shake first, then with ice.
3. Fine strain into a chilled coupe, or pour over fresh ice in a rocks glass.
4. Express a lemon twist over the drink and drag a few dashes of Angostura across the foam.

Without egg white, skip the second shake and serve over ice with a lemon wheel and cherry. The full build is in the rye Whiskey Sour recipe; the egg-white version has its own page, the Boston Sour.

The Pisco Sour (IBA official recipe)

1. Add 60 ml pisco, 30 ml fresh lemon juice, 20 ml simple syrup and one raw whole egg white to a shaker.
2. Shake with ice and strain into a chilled goblet.
3. Dash Amargo bitters on top of the foam.

The IBA calls for raw egg white. The FDA advises pasteurized eggs or pasteurized egg products for raw-egg recipes, especially for children, older adults, pregnant women and the immunocompromised — Difford's specifies pasteurized egg white in every egg spec — and aquafaba or a commercial foamer works in either drink. The egg white guide covers both.

Bitters on the Foam

This is the clearest point of difference between the two traditions. In the Pisco Sour the dashes of Amargo bitters on the foam are written into the IBA recipe: they are the garnish and the aroma, and the drink is not finished without them.

In the Whiskey Sour they are a modern import. Jerry Thomas's 1887 recipe "ornament[s] with berries"; the IBA's Whiskey Sour garnish is a half orange slice and a maraschino cherry. Bitters arrived with the egg-white revival: Difford's shakes three dashes of Angostura into its Whiskey Sour, and in PUNCH's 2024 contest nearly every entry dashed Angostura on the foam (one used Peychaud's). The judges' reason was practical — it masks egg aromas. Tales of the Cocktail's aquafaba Whiskey Sour finishes the same way. The garnish guide covers the patterns and the alternatives.

Origins: Lima, Iquique and the American Record

The Pisco Sour is long credited to Victor Morris, an American who opened Morris' Bar in Lima on 1 April 1916, though a 1903 Lima pamphlet shows an earlier "Cocktail" recipe, so the attribution is not settled.

The Whiskey Sour's paper trail is American and older. Thomas's 1862 guide prints the first known written sour recipes — Brandy, Gin and Santa Cruz — and "whisky sour" is in print by January 1870 in Wisconsin's Waukesha Plaindealer. The two drinks cross paths in one story: a legend that an English ship's steward, Elliott Stubb, invented the whisky sour in Iquique — then Peru, now Chile — in 1872. The story is in print by 1962 and became popular in Chile in the 1980s; it is told as the Pisco Sour's origin, but Difford's notes that the quote attributed to Stubb was actually about the Whiskey Sour, the Pisco Sour's forerunner, and that the Whiskey Sour's origins lie earlier in the United States, so treat it as folklore. The full account is in the history of the Whiskey Sour and who invented the Whiskey Sour.

How They Taste

Rye's job in a Boston Sour is to be heard through the foam, which is why PUNCH's 2017 judges thought it "the stronger choice" against egg white and why a 100-proof bottle like Rittenhouse Bottled-in-Bond Rye keeps winning. Pisco brings perfume rather than spice, and the extra lemon keeps it from turning soft. The rye Whiskey Sour flavor profile goes element by element through the whiskey side.

Which Is Stronger?

They are close. Both put about 2 oz of spirit into a drink with an ounce and a half to an ounce and two-thirds of citrus and syrup, plus egg white and the shake's dilution. Difford's calculates its egg-white Whiskey Sour at 16% alcohol by volume, and a Pisco Sour built to the IBA spec lands in the same neighborhood. The spirit's proof is what moves either drink: a bonded rye adds a little strength over a standard bottling, and a barrel-proof rye such as Sazerac Rye Full Proof at 125 proof adds a lot.

Which Should You Order?

One Shelf for Both

• Rye whiskey, 100 proof — the Bottle Library ranks the candidates for the sour.
• Pisco — the Pisco Sour's only bottle beyond the shared kit.
• Lemons — both drinks use lemon, squeezed within a few hours: fresh lemon guide.
• Simple syrup — 1:1 for both: syrup guide.
• Pasteurized egg white and bitters — Angostura for the Whiskey Sour, Amargo for the Pisco Sour. Shaking technique is in how to shake a Whiskey Sour.

The Rest of the Egg-White Family

The Whiskey Sour has egg-white cousins of its own. The New York Sour floats red wine on top, and Difford's version adds optional egg white too. The Rattlesnake, from Harry Craddock's 1930 Savoy Cocktail Book, is an egg-white rye sour with absinthe. Morgenthaler's Amaretto Sour pairs amaretto with cask-proof bourbon and egg white. And on the other side of the family table, the Whiskey Sour vs Margarita comparison covers the sour template without the foam.

Frequently Asked Questions

What is the difference between a Whiskey Sour and a Pisco Sour?

Both are shaken sours with lemon, sugar syrup and (in the Pisco Sour always) egg white. The Whiskey Sour uses rye or bourbon and makes egg white optional; the IBA Pisco Sour uses 60 ml pisco, 30 ml lemon, 20 ml simple syrup and one egg white, with Amargo bitters dashed on the foam.

Does a Whiskey Sour have egg white like a Pisco Sour?

Optionally. The IBA lists it as optional and Jerry Thomas's 1887 recipe has none. With egg white the drink is commonly called a Boston Sour (PUNCH, Difford's). In a Pisco Sour, egg white is part of the standard spec.

Why are there bitters on top of a Pisco Sour?

They are part of the IBA recipe — dashes of Amargo bitters on the foam for aroma. Whiskey Sours borrowed the habit later: in PUNCH's 2024 contest nearly every entry dashed Angostura on the foam, and the judges said it masks egg aromas.

Which is stronger, a Whiskey Sour or a Pisco Sour?

They are close: both use about 2 oz of spirit with similar amounts of citrus, syrup and egg white. Difford's puts its egg-white Whiskey Sour at 16% alcohol by volume; a Pisco Sour lands nearby. The spirit's proof decides which is higher.

Was the Whiskey Sour invented in Peru or Chile?

Almost certainly not. A legend credits Elliott Stubb, an English ship's steward, with inventing it in Iquique in 1872, but Difford's notes the quote attributed to him was actually about the Whiskey Sour, the Pisco Sour's forerunner, and "whisky sour" is in American print by January 1870. Treat the story as folklore.

Is raw egg white safe in a sour?

The FDA warns fresh eggs can carry Salmonella and advises pasteurized eggs or egg products for raw-egg recipes, especially for children, older adults, pregnant women and the immunocompromised. Difford's specifies pasteurized egg white; aquafaba (about 1 oz) is an egg-free alternative.