A cousin of the iconic whiskey sour, a Boston Sour adds an egg white to provide a thick, frothy foam with a silky smooth mouthfeel. Garnished well, this sweet-tart cocktail turns heads and goes down easy. As the creamy egg foam hits your lips, the citrus flavor hits you by surprise.
Technique Is Critical
To achieve the froth on top, utilize the dry shake technique. Many bartenders raise a valid point and advocate a reverse dry shake or utilize an iSi whipper to create an even thicker head. In this case, the easier and quicker dry shake achieves the desired result for most connoisseurs. To complete the dry shake, add the egg white, lemon juice, sweetener (simple syrup in this recipe), and the whiskey. For those using bitters in the Boston Sour, add them prior to the dry shake, unless you plan to use them later as a garnish.
Some bartenders recommend performing the dry shake without the base spirit, preferring to add the spirit after the dry shake and before the final shake. We add the base spirit with the rest of the ingredients and believe that it improves the mouthfeel of the end product. Those that wait to add the base spirit claim that its early addition adversely affects the emulsification and aeration of the drink. Finally, others also take the spring from a Hawthorne strainer and place it inside the mixing tin to act as an additional whisk, but we find that an unnecessary step–especially in a busy bar.
After completing the dry shake, add some ice and shake again to chill the drink. Some bartenders use a single large cube, a large cube with a couple of standard cubs, or just a few standard cubes. Whichever method you prefer, the general idea is to not destroy the froth by adding too much ice. This is where advocates of the reverse dry shake offer the classic “I told you so,” but other bartenders subscribe to the theory of postponing any dilution of the cocktail until the last step. The choice remains with the individual and these are just more examples of great, but endless debates among bartenders that few customers actually notice.
When straining the drink, we use just a Hawthorne strainer but others also fine strain the mix as it comes out to keep out any eggshells, curdled egg, or chalaza from the end product. It certainly does not hurt the drink to add a double strain, nor does it take much additional time so proceed either way.
We love bourbon in the Boston Sour, but any whiskey works and each imparts subtle flavor differences. As discussed above, variation in techniques occurs so, of course, use your preferred method. Our recipe uses simple syrup as a sweetener but the use of maple syrup remains common and often preferred. While we do not use bitters, many do, generally preferring Angostura. We served the Boston Sour up, but others prefer it on the rocks or over a single large cube. Finally, garnishes vary with presentations using combinations of lemons, oranges, and cherries. Wheels, peels, and wedges all present nicely in the Boston Sour. Laying Angostura bitters over the foam certainly makes this drink even more visually enticing while also providing an aromatic effect.
- Vegetable peeler
- Coupe glass
- Hawthorne strainer
- 2 oz whiskey
- ¾ oz simple syrup
- ¾ oz lemon juice
- 1 egg white
- orange peel and a cocktail cherry for garnish
- Prepare your garnish. All you need is an orange peel and a cocktail cherry. There are no limits to creativity.
- Chill the coupe glass.
- Add whiskey, lemon juice, simple syrup, and an egg white to the shaker.
- Perform a dry-shake--shaking without ice for a solid fifteen seconds. The harder your shake, the creamier your drink. Next, add a few cubes of ice to the shaker and shake for another fifteen seconds to chill the drink.
- Discard the ice from the coupe glass, and strain the drink with a Hawthorne strainer.
- Garnish the drink.