Whiskey · Sour · Sour
Boston Sour Recipe
The Whiskey Sour, made silkier. Silky and citrus-forward with a cloud of pale foam softening the bourbon underneath, it's an easy, unfussy sour built for slow evening sipping.
- Prep Time
- 2 min
- Method
- Shaken
- Glass
- Coupe glass
- Strength
- Balanced
Every recipe on Sipped Right is tested for taste and balance before it's published.
Last updated October 20, 2026
About the Boston Sour
A Boston Sour is simply a classic Whiskey Sour with egg white made mandatory rather than optional, giving the drink a silky texture and a pale, frothy foam cap. It's frequently mixed up with the New York Sour — a related but different drink built the same way, minus the egg, and finished with a red wine float instead.
The Boston Sour follows the classic 2:0.75:0.5 bourbon-lemon-syrup backbone of a Whiskey Sour, then adds 0.5 oz egg white as a required fourth part — that egg white is exactly what separates a 'Boston' Sour from a plain Whiskey Sour, building the silky body and pale foam head. It's a close relative of the Whiskey Sour (same base, egg optional) and the New York Sour (same base, no egg, red wine float on top).
Ingredients
- Bourbon whiskey2 oz
- Fresh lemon juice¾ oz
- Simple syrup (rich, 2:1)½ oz
- Egg white½ oz
- Lemon zest twist, for garnish1 twist
Method
- Measure and pour the bourbon, lemon juice, simple syrup and egg white into the shaker.
- Dry-shake (no ice) for 15 seconds.
- Add a scoop of ice to the shaker.
- Shake for 15 seconds.
- Fine-strain the cocktail into a chilled coupe glass.
- Cut a swath of lemon peel.
- Express the peel over the drink and drop it in.
Glass & Garnish
Coupe glass, chilled. Garnish with a lemon zest twist, expressed over the drink.
Notes
Dry-shaken with 2 oz bourbon, 0.75 oz lemon juice, 0.5 oz rich syrup and 0.5 oz egg white. There is no red wine float here — that belongs to the separate New York Sour.
Tools Used
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FAQ
- Can I use rye whiskey instead of bourbon in a Boston Sour?
- Yes — rye is a great substitute and a common variation. It swaps bourbon's caramel sweetness for a spicier, drier profile that stands up well against the lemon and egg white. Either way, use a mid-shelf 80–90 proof whiskey; anything too delicate gets lost under the citrus and foam.
- Is there a substitute for egg white in a Boston Sour?
- Aquafaba (the liquid from a can of chickpeas) is the standard vegan substitute — use about 0.5 oz in place of the egg white and it froths and dry-shakes almost identically. Pasteurized egg white from a carton also works and removes any raw-egg safety concern.
- What's the difference between a Boston Sour and a New York Sour?
- A Boston Sour is a Whiskey Sour with egg white added, giving it a silky texture and pale foam top — no wine involved. A New York Sour skips the egg white entirely and instead floats red wine on top of the drink. They share a base but are otherwise distinct cocktails.
- What's the traditional garnish for a Boston Sour?
- A lemon zest twist, expressed over the drink to release its citrus oils onto the foam before garnishing. Some versions add a maraschino cherry alongside it, but the zest twist is the classic, standard finish and pairs cleanly with the drink's lemon-forward flavour.
- Can I batch a Boston Sour for a party?
- Pre-batch the bourbon, lemon juice and simple syrup together and refrigerate, but add egg white fresh per drink — it needs to be dry-shaken individually to foam properly. For a crowd, pasteurized carton egg white makes single-serve shaking faster and safer than cracking whole eggs to order.
