The Boston Sour is a whiskey sour with an egg white, which makes a frothy foam at the top! It makes an ultra smooth flavor a beautiful look.
If you love a whiskey sour, have you tried a Boston sour? It’s a version of the popular drink with an egg white, which gives it a frothy foam topping. It looks beautiful and adds a whimsical element to this sweet tart cocktail. The Boston sour has a little smoother flavor than the whiskey sour, and it’s become our favorite variation on the classic. Here’s how to make it!
Don’t want to mess with the egg white? Try our Classic Whiskey Sour.
What’s in a Boston sour?
A whiskey sour is an iconic drink that goes back centuries. The first mention of it was actually in the 1870’s! It’s a sweet tart mixed drink made with whiskey, often bourbon, lemon and sugar. This classic cocktail is on the list of International Bartender Association’s IBA official cocktails. This means it has an official definition. The Boston sour just add an egg white! Here’s what’s in a Boston sour:
- Whiskey (usually bourbon)
- Lemon juice
- Simple syrup or maple syrup
- Egg white
How to make a Boston sour
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It’s easy to make a Boston sour: even the foam topping it easy once you know how to do it! Here’s what to do:
- Mix whiskey, lemon juice, maple syrup and egg white in a cocktail shaker. Shake for 15 seconds. (We like using maple syrup to sweeten cocktails instead of simple syrup: it gives them a nuanced sweetness! You can use either.)
- Add ice to the cocktail shaker and shake again for 30 seconds.
- Strain it into a glass and garnish with an orange peel. If you have it, a cocktail cherry is the most traditional. We love adding it for the classic look.
The trick to the foam topping: a dry shake!
How does it all work? Most drinks are shaken together with ice in a cocktail shaker. But in this Boston Sour you’ll do what’s called a Dry Shake. That means you’ll shake the ingredients first without ice. Then you’ll add the ice and shake again. This method is used with many cocktails that have an egg white, and results in a lovely white layer of foam on top. You’ll notice that we also use this technique in other sour cocktails like the Classic Gin Fizz, White Lady, Clover Club, Gin Sour, Pisco Sour, Tequila Sour, and Vodka Sour.
There’s another technique that gets even more foam: it’s called the Reverse Dry Shake. For this technique, you shake the ingredients with ice first, then strain out the ice and shake again. We like the texture of the foam in a dry shake, and it’s most common for classic cocktails.
What type of whiskey for a Boston sour
As with any cocktail: you’ll want a good quality whiskey for this Boston sour. The better quality the alcohol, the better the drink. Look for a mid-price range whiskey. Bourbon is usually what is used in a whiskey sour, and we prefer it in our Boston sour as well. (If you love bourbon, try all our Great Bourbon Cocktails!)
Vegan egg white substitute for cocktails
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Is there a vegan egg white substitute in cocktails? Yes: aquafaba. What’s that? Aquafaba is the liquid that’s in a can of chickpeas. Because it’s so starchy, it can work as a binder similar to an egg. Since 2 tablespoons of aquafaba equal 1 egg white, you can use 2 tablespoons of aquafaba in this recipe as an equivalent to the actual egg white. It makes for the same type of foam!
What cocktail shaker to use
Cocktail shakers are absolutely worth having if you find yourself making lots of cocktails! It’s a important tool for making this Boston Sour since shaking the cocktail helps to build the foam topping. A cocktail shaker quickly chills cocktails by shaking them against ice, and it has a perforated lid so you can pour out the cocktail without pouring out the ice. Here’s the shaker we recommend: Favorite Cocktail Shaker.
Don’t have a cocktail shaker? You can use a glass mason jar and a strainer instead! Place the cocktail ingredients in the jar and fill it with ice. Put on the top (or cover it with your hand) and shake away! When you pour the drink into a glass, you’ll need to pour it through a strainer to strain out the ice.
When to serve a Boston sour
The Boston sour is a classy classic cocktail that’s delicious as it is versatile. It’s perfect for sipping as a:
- Happy hour drink
- Dinner party drink
- Summer patio drink
- Late night drinks drink
- Guys or girls night drink
- Cocktail hour drink
More classic cocktails
Here are a few more of our classic cocktails to add to your repertoire:
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- Best Gin and Tonic Here are the keys to the very best gin and tonic, the most refreshing 2-ingredient cocktail! A few secrets take this crisp, botanical drink over the top.
- Tom Collins Cocktail This popular sweet sour cocktail is light and bubbly! Don’t forget the cherry.
- Prosecco Mimosa Here’s the best mimosa recipe! This one’s made with Italian Prosecco, orange juice, and a dash of Cointreau for the perfect bubbly tart flavor.
- Classic Margarita The very best classic margarita: lime, tequila and Cointreau. Perfection!