Boston Sour

Pro tips

• Dry shake first (without ice) for 10–15 seconds to fully emulsify the egg white before adding ice and shaking again—this creates the thickest foam.
• Chill your glass beforehand; a cold surface helps the foam set and last longer.
• Use fresh lemon juice, not bottled; the bright acidity balances the sweetness and whiskey weight.
• Powdered sugar dissolves faster than granulated in the shake and produces a silkier mouthfeel.

Substitutions

• Old Thompson Blended Whiskey → bourbon or rye whiskey (rye adds spice; bourbon adds sweetness)
• Powdered Sugar → 3/4 tsp simple syrup (closer to classic Sour proportions but less silky texture)
• Egg White → 1/2 oz aquafaba or 1/4 tsp xanthan gum dissolved in water (vegan alternatives; texture differs slightly)

Equipment

cocktail shaker · jigger or measuring spoon · strainer · barware (mixing glass optional)

Can I make a Boston Sour without egg white?

Yes. Omit the egg white for a lighter, sharper drink, though you'll lose the signature creamy texture and foam top.

Is it safe to drink raw egg white in a cocktail?

Use pasteurized eggs or pasteurized egg white product to minimize food safety risk. Some bars use these by default.

What's the difference between a Boston Sour and a regular Whiskey Sour?

A Boston Sour specifically includes egg white for texture and foam; many Whiskey Sours skip it or use simple syrup instead of powdered sugar.

How do I get a good foam layer?

Shake hard and long (15–20 seconds) with ice to aerate the egg white, then strain into a chilled glass and pour the foam last.