Try This Rum Old Fashioned Recipe With A Smoky Twist
If you’ve never tried a Rum Old Fashioned, you’re in for a smooth, sultry twist on the classic cocktail.
I first had a Rum Old Fashioned on a warm spring night in Charleston. My husband and I had wandered into a little jazz bar tucked behind an art gallery off King Street. It was one of those places where the lights are low, the bar is heavy with oak, and the bartender clearly knows more than you do about liquor. I ordered the usual bourbon Old Fashioned, but the bartender gently suggested I try his version with aged rum and a touch of molasses syrup. I didn’t argue, and thank goodness I didn’t. That drink had all the warmth of a Southern evening and a depth of flavor I couldn’t stop thinking about. It had this cozy, slow-sipping richness that wrapped around me like a soft breeze off the harbor. The molasses gave it a slightly smoky sweetness, and the rum brought in warm spice without that hard whiskey kick. I kept stealing sips long after I said I was done.
Once we got home, I made it my mission to recreate that exact combination. I tried a few rums, played with different syrups, and finally landed on the mix that brought me right back to that little corner bar. The result is this Rum Old Fashioned recipe, and I think you’re going to love it.
Why This Rum Old Fashioned Recipe Works
This cocktail is built for folks who enjoy a spirit-forward drink but want something a little more mellow than whiskey. Aged rum is smooth and flavorful, with layers of molasses, vanilla, and spice that create a deep and complex base. It holds its own in a classic format without the sharp edge bourbon can sometimes bring.
The best rums for this are the ones that have spent some time in a barrel. That aging process adds warm notes like oak, toffee, dried fruit, and sometimes even a bit of nuttiness. When paired with bitters and a dark sweetener like demerara syrup or molasses, the whole drink turns into something richer, darker, and more relaxed. It’s perfect for sipping slow, especially when the day winds down and you’re ready for something a little indulgent but still grounded.
You still get that strong, stirred-down cocktail feel. But the rum brings in a rounder, more relaxed character that gives the drink a personality all its own.
Ingredients For This Rum Old Fashioned Recipe
- 2 oz aged or dark rum (try Diplomatico Reserva, Mount Gay XO, or Appleton Estate)
- 1/2 oz demerara syrup (or molasses syrup for a Southern twist)
- 2 to 3 dashes Angostura bitters
- Orange peel, for garnish
- Large ice cube or sphere
The key ingredient here is the demerara syrup or molasses syrup. It gives the drink a smoky sweetness that plays beautifully with aged rum. You can find demerara syrup at most liquor stores, or make it at home by combining equal parts demerara sugar and water. If you use molasses syrup, go easy on the quantity. It’s bolder and richer, and a little goes a long way.
Step-by-Step Instructions For Rum Old Fashioned
- Add the syrup and bitters to a mixing glass.
Start with 1/2 oz demerara syrup and add 2 or 3 dashes of Angostura bitters. If you’re using molasses syrup, stick with about 1/4 oz unless you want it extra rich. - Pour in the rum.
Add 2 oz of aged or dark rum. Don’t use a white rum here. It won’t hold up to the bitters and syrup the way an aged rum does. - Fill with ice and stir.
Stir with a bar spoon for about 20 to 30 seconds until the drink is well chilled. This dilutes the drink just enough to mellow the flavors and tie everything together. - Strain into a rocks glass.
Use a Hawthorne strainer and pour the drink over a large ice cube. The large cube keeps it cold without watering it down too fast. - Garnish.
Express the oils from a fresh orange peel over the drink, then drop it in.
If you want to experiment, try adding a dash of chocolate bitters alongside the Angostura. It adds a rich undertone that works especially well with molasses syrup.
Try This Rum Old Fashioned Recipe With A Smoky Twist
This Rum Old Fashioned is a sultry Southern twist on the classic cocktail. Made with aged rum, demerara or molasses syrup, and aromatic bitters, it’s a warm, rich drink perfect for slow sipping on cozy evenings.
Ingredients
- 2 oz aged or dark rum (such as Diplomatico Reserva, Mount Gay XO, or Appleton Estate)
- 1/2 oz demerara syrup (or 1/4 oz molasses syrup for a bolder twist)
- 2–3 dashes Angostura bitters
- Orange peel, for garnish
- Large ice cube or sphere
Instructions
- Add the demerara or molasses syrup and bitters to a mixing glass.
- Pour in the aged rum.
- Fill the glass with ice and stir for 20 to 30 seconds until well chilled.
- Strain into a rocks glass over a large ice cube.
- Express the orange peel over the drink to release the oils, then drop it in as garnish.
- Serve immediately and sip slowly.
Notes
For the best flavor, use a high-quality aged rum with depth and character.
Demerara syrup adds rich molasses flavor without overpowering the drink, but if you're feeling bold, molasses syrup brings an extra smoky-sweet intensity.
A large clear ice cube helps chill the cocktail without diluting it too fast.
How To Serve A Rum Old Fashioned
This drink deserves a proper presentation. Serve it in a short, heavy-bottomed rocks glass, preferably with a large clear ice cube to slow dilution. That clean, cold cube keeps the drink balanced without getting too watery.
I like serving a Rum Old Fashioned during the evening hours, maybe right before dinner or after the kids go to bed. It’s a slow sipper, meant to be enjoyed without rushing. If you’re hosting, it pairs beautifully with small bites like:
- Spiced nuts or candied pecans
- Bittersweet dark chocolate squares
- Smoked bacon-wrapped dates
It also plays well as an after-dinner drink, especially if you’re serving something rich like a flourless chocolate cake or bread pudding.
How To Store & Re-Use Rum Old Fashioned Leftovers
If you’re mixing drinks ahead of time, you can pre-batch a Rum Old Fashioned without ice or garnish. Just combine the rum, syrup, and bitters in a sealed container and store it in the fridge. It will keep well for up to 3 days.
When you’re ready to serve, just give it a good stir with ice and strain it into a glass. Add your fresh orange peel garnish then.
As for the syrup, whether you use demerara or molasses, it stores well in the fridge for up to a month in a sealed jar. Leftover syrup is great in:
- Hot coffee
- Iced coffee or cold brew
- Homemade whipped cream
- Drizzled over pancakes or waffles
If you’re feeling bold, try using it as a glaze base for baked ham or roasted carrots.
Substitutions & Variations For Rum Old Fashioned
There’s plenty of room to make this drink your own. Here are a few swaps and spins you might enjoy:
- Spiced Rum: This adds a more aromatic flavor profile. Look for something smooth with natural spices, not overly sweet.
- Sweetener Swaps: Maple syrup and honey syrup both work well. Maple gives it a more woodsy depth, while honey softens the rum’s edge.
- Tropical Twist: Add a splash of falernum or allspice dram to give it a tiki-style flavor.
- Citrus Lift: Try a lemon peel garnish instead of orange for a brighter aroma.
- Wisconsin-Inspired: Garnish with an orange slice and cherry for a nod to the Brandy Old Fashioned tradition.
I sometimes even stir in a bar spoon of pineapple gum syrup if I want something fruit-forward without going full tropical.
What Is a Rum Old Fashioned?
A Rum Old Fashioned is a riff on the classic whiskey cocktail, using aged rum in place of bourbon or rye. It follows the same traditional structure: spirit, sugar, bitters, and citrus garnish.
What makes the rum version stand out is its warmth. Aged rum has molasses and oak character, with notes of vanilla, toffee, and dried fruit. That makes it a fantastic base for an Old Fashioned, especially when paired with rich sweeteners like demerara syrup.
This cocktail is perfect for folks who want a simple old fashioned recipe with a unique spin. It feels classic but leans into the laid-back flavor of the Caribbean.
FAQs About Rum Old Fashioned Recipe
Here are some straightforward answers to the most common questions I receive about this rum old fashioned recipe.
1. What kind of rum is best for a Rum Old Fashioned?
Look for a dark or aged rum that has depth and character. Rums labeled “anejo,” “reserva,” or “extra old” tend to work well. Some favorites include Mount Gay XO, Appleton Estate 12 Year, and Diplomatico Reserva Exclusiva. You want something that can hold its own against bitters and syrup without disappearing into sweetness.
2. Can I make a Rum Old Fashioned without bitters?
You can, but the drink loses some of its balance. Bitters add a touch of spice and help tie the sweetness and spirit together. If you’re out of Angostura, try another aromatic bitter like Fee Brothers Old Fashioned Bitters or even chocolate bitters for something a little different.
3. What’s the best sweetener for a Rum Old Fashioned?
Demerara syrup is my top choice. It has a richer flavor than white sugar syrup and pairs beautifully with aged rum. Molasses syrup adds even more depth but needs to be used in smaller amounts. Maple syrup is a fun fall alternative, while honey syrup gives it a floral lift.
4. Is a Rum Old Fashioned sweeter than the whiskey version?
It can be, especially if you’re using a sweeter rum or a heavier hand with the syrup. But with proper balance, it shouldn’t be cloying. The bitters and citrus help keep things grounded.
5. Can I batch a Rum Old Fashioned for a party?
Yes. Combine the rum, bitters, and syrup in a large pitcher or bottle without any ice or garnish. Store it in the fridge until you’re ready to serve. Stir each drink with ice right before serving and garnish fresh. For batching, multiply the recipe by the number of servings and taste to adjust sweetness.
Try These Recipes Next
If you enjoyed this rum old fashioned recipe, here are a few other cocktails I think you’ll love:
- The 10 Best Old Fashioned Cocktail Recipes – A roundup of creative spins and tips for mastering the old fashioned in all its delicious forms.
- Classic Old Fashioned Recipe: A no-frills, traditional Old Fashioned made with rye or bourbon, bitters, and a sugar cube. Simple, elegant, and always in style.
- Tequila Old Fashioned Recipe: A bold southwestern twist made with aged tequila, cinnamon syrup, and orange bitters. Smooth, spicy, and perfect for sipping under string lights.
Whether you’re lounging on the porch or mixing drinks for company, this Rum Old Fashioned brings a little extra soul to the glass. It’s rich, relaxed, and full of charm, just like a good Southern evening should be.