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Rum Sour is the whiskey sour”s warmer, slightly tropical cousin, dark rum shaken with fresh lemon and simple syrup under a silky egg white foam that makes every glass look professionally poured. I shook my first one on a Friday night in and immediately understood why sours have survived 150 years of cocktail trends. If my French 75 covers the bubbly end of classic cocktails, this covers the silky end.
Four ingredients, two shakes, and a foam top that does all the showing off.
Rum Sour Quick Look
- 🕒 Prep Time: 3 minutes
- 🌡️ Cook Time: 0 minutes
- ⏳ Total Time: 3 minutes
- 🍽️ Serving: 1 drink
- ⚡ Calories: 210kcal
- 🌶️ Flavor Profile: Warm molasses rum against bright lemon under silky foam
- ✋ Difficulty: Easy, a two stage shake is the only technique
Quick Answer
Add 2 ounces of dark rum, 1 ounce of fresh lemon juice, three quarters of an ounce of simple syrup, and one pasteurized egg white to a cocktail shaker with no ice. Seal and dry shake hard for 30 seconds to build the foam. Add a handful of ice, shake again for 20 seconds until well chilled, then strain into a coupe glass. The foam settles into a silky white cap, garnish with a dried lemon wheel and skewered cherries.
Jump to:
Why This Recipe Works
Click to see the technique science
- The dry shake builds the foam. Shaking the egg white without ice first lets it unwind and aerate at room temperature, that is the entire secret to a thick, stable foam cap.
- Fresh lemon is non negotiable. Bottled juice tastes cooked and flat, one fresh lemon gives the bright acidity that balances the molasses notes in dark rum.
- The 2 to 1 to 3/4 ratio is the sour gold standard. Two parts spirit, one part citrus, three quarters part sweet is the template behind every great sour, it lands perfectly balanced every time.
- Dark rum brings built in depth. Aged rum carries vanilla and caramel from the barrel, so the cocktail tastes layered with only four ingredients.
- Egg white changes texture, not flavor. It is flavorless in the finished drink, what it adds is that plush, velvety mouthfeel that separates a sour from rum lemonade.
Why You’ll Love This Recipe
- It drinks like a craft bar cocktail but needs exactly four ingredients and a mason jar will do as the shaker.
- The recipe is a template, once you own the ratio you can sour any spirit on the shelf.
- The foam top makes it look like a 15 dollar bar pour, the same effect that sells my passion fruit gin fizz.
Key Ingredients
Four pours build the drink, two extras dress it up.
- Dark rum: An aged gold or dark rum brings caramel depth, Bacardi Gold is the workhorse pour here.
- Fresh lemon juice: One lemon per drink, squeezed fresh, the brightness the whole cocktail balances on.
- Simple syrup: Store bought or homemade, it sweetens without the graininess of straight sugar.
- Pasteurized egg white: The foam engine. Carton egg whites are pasteurized and pour ready, no separating required.
- Dried lemon wheels and maraschino cherries: The classic garnish pair that floats on the foam.
See recipe card for exact quantities.
Variations and Substitutions
The sour template takes every spirit and season.
- Use white rum for a lighter, crisper sour that leans daiquiri.
- Float a half ounce of red wine on top for a rum New York sour, the layered look is spectacular.
- Swap the simple syrup for honey syrup for a warmer, rounder sweetness.
- Swap the dark rum for tequila and you are basically at my margarita, the sour template is that flexible.
- Skip the egg white entirely for a lighter shake and serve it over ice, still delicious, just less velvet.
How to Make Rum Sour
- Add the dark rum, fresh lemon juice, simple syrup, and egg white to a cocktail shaker without ice.
- Seal and dry shake hard for 30 seconds. No ice means the egg white aerates fully, you will feel the drink foam up and get lighter as you shake.
- Open the shaker, add a handful of ice, reseal, and shake again for about 20 seconds until the shaker is frosty cold.
- Strain into a chilled coupe glass and let the foam settle into a smooth white cap, then garnish with a dried lemon wheel and skewered maraschino cherries.
Recipe Tips & Tricks
- Dry shake longer than feels necessary. Thirty full seconds builds a foam that holds, fifteen gives you bubbles that vanish.
- Use pasteurized carton egg whites. Same foam, zero raw egg worry, and no yolk separating over the sink.
- Chill the coupe in the freezer first. A cold glass keeps the foam tight and the drink cold to the last sip.
- Strain, do not pour. Holding the ice back gives you the clean two layer look instead of a slushy top.
- Aquafaba works for an egg free foam. One ounce of chickpea liquid whips up nearly identical, shake it the same way.
- Garnish on the foam, not in it. Rest the lemon wheel gently so it floats, dropping it punches a hole in your work.
Serving Ideas and Suggestions
Serve the rum sour as the opener at a cocktail night alongside my creamy painkiller cocktail, one bright and silky, one tropical and rich, rum both ways.
For a dinner party, it pairs beautifully with rich food, pour it next to a cheese board while a pitcher of my white wine sangria handles the wine crowd.
Summer patio session? Shake these while my blueberry lemonade cocktail covers the frozen drink fans, the lemon theme ties the menu together.
And for a nightcap, a rum sour with a couple of dark chocolate squares is quietly one of the best pairings in the cocktail world.
Rum Sour FAQs
Dark rum, fresh lemon juice, simple syrup, and an egg white, shaken twice and strained into a coupe. It follows the classic sour ratio of 2 parts spirit, 1 part citrus, and three quarters part sweetener, with the egg white adding the signature silky foam cap.
Same template, different personality. Swapping bourbon for aged rum trades the oaky spice for caramel and molasses warmth, so the rum sour drinks slightly rounder and more tropical. If you love one, you are about one shake away from loving the other.
Use pasteurized egg whites from a carton and the concern disappears, they foam almost identically to fresh. The citrus and alcohol also create a hostile environment for bacteria, which is why egg white sours have been a bar standard for over a century.
Yes, just shake the rum, lemon, and syrup with ice and strain, you lose the foam but keep the balance. For a vegan foam, use an ounce of aquafaba, the liquid from a can of chickpeas, it dry shakes into a nearly identical silky cap.
A gold or aged rum in the Bacardi Gold range hits the sweet spot, enough barrel character to stand up to the lemon without a premium price. Dark Jamaican rum makes a bolder, funkier version, and white rum a lighter one, all three work with the same ratio.
The dry shake was too short or skipped. The egg white needs 30 seconds of hard shaking without ice to aerate, then the ice shake chills and tightens the foam. Old egg whites also foam poorly, fresh carton whites give the most reliable cap.
Made this Rum Sour? Leave a comment and a star rating below, and tell me which spirit you are souring next!
Rum Sour
Ingredients
- 2 ounces dark rum
- 1 large pasteurized egg white
- 3/4 ounce lemon juice fresh squeezed
- 3/4 ounce simple syrup
- Dried lemon wheels garnish, optional
- Luxardo maraschino cherries garnish, optional
Instructions
- Pour the dark rum, pasteurized egg white, fresh lemon juice, and simple syrup into a cocktail shaker.
- Place the top on the cocktail shaker and dry shake vigorously for 30 seconds until it becomes frothy.
- Next, we are going to wet shake by adding a handful of ice cubes to the shaker and putting the top back on. Shake vigorously again for 1 minute.
- Strain the cocktail into a chilled glass and garnish with dried lemon wheels and cherries on the top of the drink.
Notes
- This can be made vegan, see my tips above on egg white substitutions.
- Tons of custom garnish options, see my tips above on that.
- It cannot be stored, best served immediately.
- Make your own dried lemon wheels, scroll up to see my tips.
Nutrition
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