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How to Make a Boston Whiskey Sour (and a Vegan one)

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Classic Boston Sour with flower garnish
Classic Boston Sour (Vegan)

I love a great Boston whiskey sour, even though it has egg white in it. But for years I didn’t order Boston sours because I worried that I’d be able to taste the raw egg in it. Finally, at a bourbon event we had a bourbon sour that used egg whites and I was won over with the first sip.

Let me tell you why. . .

And it’s not just the foam. But, oh, that creamy, delicate foam on the top of the cocktail!

Here’s why: the smooth, creaminess of the cocktail, its more delicate flavors, and the way the garnish floated on top of the foam. I always say you drink first with your eyes when you’re presented with a cocktail. And a great foam on a lovely sour is a pillow for delicate and herbal garnishes.

(This is part 2 of a three part series on the whiskey sour. The first covers a basic whiskey sour and it’s history. In this one we cover the Boston (egg white/foamy) sour and in the next a New York Sour – with that red wine float.)

(Post may have affiliate links.)

How Egg Whites Change a Cocktail

Classic Boston Sour with flower and bitters to garnish
Classic Boston Sour (Vegan)

Egg whites make three major changes to the perception of taste in a cocktail. If you don’t trust me, make two versions of the whiskey sour and do a taste test. In the second, add ¾ oz egg white or aquafaba and tell me you can’t taste a difference.

  1. They cut down on the acidity and can soften the sweetness of a cocktail.
  2. They also lessen the tannic and oaky flavors – which can be a good thing, depending on the whiskey you’re using.
  3. The addition of tiny air bubbles throughout the cocktail makes gives it a creamy texture in the mouth. It also gives it that lovely layer of foam on top.

Why Egg Whites Change a Boston Sour

In the same way that a chef might use vigorous whipping to push the proteins in egg whites into a meringue, the cocktail shaker attempts to do the same thing, adding air to the combination of egg whites, acid and sugar to create tiny bubbles in the cocktail.

Basically, you’re making the start of a meringue in your cocktail, and you have the smooth, silky texture of  meringue combined with the sour, sweet and spirit of your flavors. Like a meringue, the production of the Boston sour requires arm work, except I’ve got a short cut for those of you with shoulder problems who still want a great foam top on your sour.

Tips for Using Eggs in your Whiskey Sour

eggs in an open carton
Eggs in a carton. Photo by Tookapic

We’ve heard for ages that raw eggs are dangerous (yet still I would eat raw cookie dough and cake batter – don’t judge). Salmonella has been found on eggshells, so you must be extremely careful when working with eggs and cocktails. (Or just head down to the Vegan Whiskey Sour section for safer and less animal- cruel way to make your Boston sours).

So, I’ve got some easy tips to keep yourself and your guests safe when drinking cocktails with egg whites.

1. Fresh Eggs Only

Use only fresh, un-expired eggs. And only eggs whose shells are unblemished/whole – no cracks!

2. No Brainer – You Know This

Keep your eggs refrigerated.

3. Consider Pasteurized Eggs

If you are worried about safety, purchase pasteurized whole eggs. They’ve been treated so that their shells are not contaminated by salmonella or other dangerous bacteria.

According to Dave Arnold in Liquid Intelligence (fabulous book on the science behind cocktails – highly recommended), the pasteurized egg whites sold in cartons make for terrible egg white cocktails and should be avoided. I haven’t worked with them so can’t comment from first-hand experience. But he’s done extensive taste tests and perceives a noticeable degradation in the taste of cocktails using those egg whites in cartons.

4. Wash Your Hands

Use clean hands, and don’t let the egg white touch the shell as it cracks. Use a slotted spoon, an egg white separator or your very, very clean hand to separate the white from the yolk, not the shell.

5. Let Your Guests Know There’s Raw Egg

Warn any guests you’re serving that the cocktail has raw egg in it. Some folks have allergies or food sensitivities you want to avoid triggering with your gorgeous cocktail. If you’re not sure, head on down to the Vegan Whiskey Sour section for an alternative.

Vegan Whiskey Sours are the Best

whiskey sour with watermelon and mint garnish
Watermelon Sour – Meloncholy

You probably don’t know that I’m a vegan. I don’t talk about it a lot because it’s a dietary restriction for me. One thing I have missed has been the creamy mouthfeel you can have in cocktails with egg whites. But I have GREAT news for you.

Have you heard of aquafaba?

It’s a vegan option you can use to get that same creamy mouthfeel and reduction in harsh flavors that you can with egg whites. And you can find it easily in your local grocery store.

What is Aquafaba?

Aquafaba is the soak water from cans of chickpeas. That’s it. It’s just the bean water you would normally drain from the can before using the garbanzo beans. Reserve it the next time you’re using a can of garbanzos and you have your aquafaba for your next sour.

Aquafaba is nearly flavorless, like egg whites, and it has the same abundance of proteins that allow that frothy, creamy mouthfeel and lovely head of foam on top.

It keeps for several days, but I have better foam when it’s fresh. You use the same amount you would as egg white – generally about ¾ an ounce. It doesn’t add any off flavors or strange aromas, and it’s completely vegan.

Here’s how to “harvest” aquafaba from a can of chickpeas.

  1. Open a can of chickpeas
  2. Drain the beans in a collander and reserve the liquid
  3. Keep the liquid in the fridge for up to a week to make cocktails (although fresher is better)

Did you know the reason mixologists drop or spray bitters on the top of egg white cocktails is to disperse the wet-dog smell that sometimes develops after 10 or 15 minutes? Many Boston sours use aromatic garnishes for the same purpose.

A Did You Know Tip

The Traditional Way to Get Foam on a Whiskey Sour

In the same way I was intimidated by putting egg whites in my cocktails, I was not looking forward to destroying my shoulders putting in the work to get that lovely froth on top of a Boston sour. Most bartenders I talked to were talking about shaking for a minute or more.

There are two methods, the dry shake and the reverse dry shake.

Dry Shake

The dry shake has you place the contents of the cocktail in a shaker without ice (dry) to shake for about a minute (a minute of shaking is a very long time when you’re actually shaking). Then you add ice and shake again, double strain and serve.

Reverse Dry Shake

But others advocate the reverse dry shake. In the reverse dry shake you shake the Boston sour with ice first to chill it, strain out the ice and shake again (in the same cold shaker) to add more air to the cocktail without further dilution. This gives you that beautiful foamy top you’re looking for in the Boston sour.

If you lurk around the major cocktail sites there are proponents of both sides, and still others that say shaking extremely vigorously with ice once for about a minute and then double straining will yield the same results.

If I’m making egg-white whiskey sours at home, I’m likely to use the dry shake and not worry about a huge foamy head on my cocktail. But if I’m taking pictures or making one for someone else and I want to really get that creamy, foamy texture I break out my trick hack: a milk frother.

Easy (Cheat) Way to Get Foam on a Whiskey Sour

whisk end of milk frother for Boston Sour
Classic Boston (Vegan) Sour preparation

Now that I’ve documented the traditional way to get that lovely foam on top of a Boston whiskey sour, let me tell you how to it in a few seconds with a push of a button.

It may be cheating, but I am going to tell you that for my purposes, using a milk frother – a tiny handheld whisk – is faster, easier and more consistent with foam for sours than building it by hand.

I found the tip on the Garnish Blog and immediately ordered at $15 milk frother. Designed for lattes and coffee drinks I was very doubtful that it would work. To my delight it is easy, fast and doesn’t require long bouts of shaking.

Here’s how I use it:

  1. I put the cocktail contents in the shaking tin, add ice and shake it vigorously until very cold.
  2. I double strain the sour into a clean mixing glass or shaking tin base and use the frother on it for about 10 to 15 seconds at most.
  3. I strain the contents of the cocktail into the coupe glass.

There’s a trick to the angle you use. You want the frother to whip up the upper layers of the cocktail, but not so much that the entire cocktail is foam. Holding it at a 45 degree angle focused on the top/outer layers of the cocktail, let the frother run for about 15 seconds and see how much foam you have. If you need more, run it for a few seconds at a time until you have your desired foam level.

Easy peasy.

The best part: we now have frothy milk lattes every morning for our coffee fix. You’ll step up your cocktail and your coffee game using this lovely tool.

Recommended Bar Tools

You don’t need every slick, beautiful bar tool out there, but there are several I’ll recommend. (As an Amazon Associate I earn from qualifying purchases. However, that does not affect the cost of the items below.) My favorite pieces usually come from the Cocktail Kingdom section of Amazon:

You may already have these bar essentials, but just in case:

Classic Boston Sour with flower garnish

Boston Whiskey Sour/Vegan Whiskey Sour

Picture of Heather Wibbels, Cocktail Contessa, pouring a cocktailHeather Wibbels
Back to basics with a standard whiskey sour recipe – whiskey, lemon, simple syrup and a touch of bitters combine to create an easy sipping tipple for a warm afternoon in the sun. Or late night by the pool.
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Course Drinks
Cuisine Bourbon Cocktail
Servings 1


  • 2 oz bourbon whiskey
  • ¾ oz fresh lemon juice
  • ¾ oz simple syrup (I used champagne simple because that's what I had)
  • ¾ oz egg white or aquafaba
  • Garnish: Angostura or Black walnut bitters dropped onto the foam


  • Combine ingredients into a shaker with one cube of ice. Shake for 30 seconds. Open the shaker, add in a heap of ice, close the shaker and shake again. This time for 30 to 60 seconds. Alternately, shake with ice first to chill, strain into a chilled mixing glass or shaker and use milk frother for 10 to 15 seconds to build the foam. Strain into the cocktail glass whichever method you use. Strain the cocktail into a chilled coupe glass and garnish with a few drops of angostura bitters dropped on the top of the cocktail.


To make the champagne simple syrup, take 1 cup of champagne and add 1 cup of sugar. Heat it just enough for the sugar to dissolve, then take it off the stove, let cool completely and refrigerate.
Keyword apple bitters, boston sour, bourbon, egg-white sour, lemon, vegan sour, Whiskey Sour
Tried this recipe?Let us know how it was!
By on August 26th, 2020
Picture of Heather Wibbels, Cocktail Contessa, pouring a cocktail

About Heather Wibbels

Heather Wibbels is a whiskey and cocktail author (Executive Bourbon Steward, no less) with a passion for cocktails. She loves researching and designing cocktails, drinking cocktails, and teaching cocktails. Mostly whiskey cocktails, given her Kentucky location.

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