Rum Old Fashioned – The Best Fall Cocktail

Last Updated on March 15, 2023 by Heather Wibbels

We’re taking fall to the next level with this rum old fashioned. I know it’s heresy to use anything other than whiskey in an old fashioned cocktail, but the original, early written descriptions of an old fashioned didn’t necessarily mention whiskey specifically. Just “spirit.”

And they weren’t talking about ghosts.

But using aged rum for a fall old fashioned sweetens the cocktail, especially with this syrup created specifically for fall cocktails. So, mix up this lovely rum drink recipe that makes you want to put on a warm sweater and sit by the fire.

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I’ve written a full article on my perfect old fashioned; it’s a great compilation of the history and elements of the cocktail. In essence it was first used as a method to take your medicine! Early cocktails included bitters with whiskey – since both were perceived to be medicinal (more on bitters here).  The three basic elements of the old fashioned became codified in the early 1900s as whiskey, sugar and bitters.

About the Rum Old Fashioned

Go forward a hundred or more years and the base spirit in an old fashioned is often replaced by something other than whiskey. Think of the Oaxacan old fashioned, or a great brandy old fashioned. Both of those change out the base spirit, but still use the addition of a sweetening agent and a bitter.

We don’t hear much about an old fashioned with rum, and that’s disappointing. Because it’s delicious!

Why This Aged Rum Cocktail Works

Rum, like whiskey, is an aged spirit. Often, it ages in used whiskey or bourbon casks, sitting for years in the Caribbean climate to soak in and out of the barrel staves over time.

As it ages, it draws notes from the wood and the spirit previously in the barrel, usually whiskey.

Like whiskey, aged rum can be complex. Often more than just caramel and vanilla aromas, dark rums can have complex floral, herbaceous and nut notes, just like whiskey. It also gives off spice notes, earthy notes and complex bitter flavors at times. Because of this complexity, rum’s a good match for the old fashioned.

Just as I prefer aged tequilas over silver tequilas, I prefer aged rums to make this mixed drink. It’s more difficult to find a higher proof aged rum to mix with.

Most producers bottle rum at 40% alcohol or 80 proof and lower than I’m using to mixing with. I understand the need to punch up tiki drinks with a bit of over-proof rum to keep it from disappearing into the drink.

However, in this case, with the Ron Viejo de Caldas (gifted as a PR sample) 8 year, the flavors are still pronounced enough to hold up at 80 proof.

I suggest diluting less than you might with a higher proof whiskey, but serve it over a single large cube with my fall simple syrup. You might be converted to a rum drinker.

Fall Cocktail Simple Syrup

I created this fall simple syrup to evoke some of the flavors and smells I associate with the season. The syrup’s notes of honey, brown sugar, baking spices and ginger fits well with both whiskey and aged rum cocktails because their flavor profiles can be so similar.

The ginger slowly heats up a bit after the syrup sits a day or two, so don’t be disappointed if it’s not as punchy as you’d like when you taste it right after making it.

Bitters for a Rum Old Fashioned

While many standard recipes for a rum old fashioned call for orange bitters, with the fall simple syrup I wanted this rum-based old fashioned to be a bit earthier and spicier than your average rum cocktail. To do that I added two spiced bitters and a dash of allspice dram.

The allspice dram works just as it does in any tiki drink. The heat and aggressive clove spice of the spirit cuts into the sweetness of the rum and simple, redefining it.

In addition, I added Old Forester’s Smoked Cinnamon bitters which are more cinnamon than smoke, but a great way to link the ginger and the rum together.

The second bitters, the Woodford Sassafras and Sorghum bitters are some of my favorite ways to add earthy, dark elements to a cocktail. They’re bitter, but in a way that makes me think of wandering through a forest trail as the leaves have fallen.

This post, originally published September 2020, was last updated in March 2023.