Let’s talk about bitters. As the name implies, they are usually bitter liquids that are used to “season” cocktails. They are made by infusing plants, berries, or barks in alcohol. Interestingly, bitters were originally used to treat upset stomachs and, in small towns in Costa Rica, your local bartender will still prescribe a shot of bitters to cure a hangover. Nowadays, they seem to be everywhere and companies have been coming up with increasingly more daring and interesting bitter flavors (Sriracha bitters, anyone?).
If you’ve never used bitters in your cocktails, this rum Old Fashioned might be a good place to start. It uses three different types of bitters to add complexity and balance to an otherwise classic drink. An Old Fashioned is pretty straightforward: it features sugar or simple syrup, bourbon or rye, and bitters. It’s name is not a coincidence; it has a long history, and it’s considered by some to be one of the “original” cocktails. If you read my previous post on how to drink better cocktails, you know that I love rum, so I just couldn’t resist seeing if I could incorporate it successfully into such a classic cocktail.
So, why all the different bitters? Let me quickly explain what I think each one adds to the drink.
Prickly Pear bitters. These are, by far, my favorite bitters. They have a wonderfully fruity aroma and add an interesting vegetable flavor to any cocktail. I got mine from a company in San Francisco called Seven Stills.
Reagan’s orange bitters. These bitters provide the strong bitter flavor that is needed to balance the sweetness from the rum and the the simple syrup.
Angostura bitters. Not only are these bitters a nod to the traditional Old Fashioned (they are the best known and most “classic” bitters in the market), but they also add some body and complexity to the drink that wouldn’t be there if you only used the other two.
Angostura and Reagan’s orange bitters are relatively easy to find, but you might have to order the prickly pear ones from Amazon or an online store specializing in bitters and spirits. If you absolutely can’t find them, you can omit them.
I’ve also chosen to use a fairly smooth and easy-to-drink rum from St. Lucia because it packs a punch without being too sweet. It’s from K&L Wine Merchants Faultline brand, so feel free to use your favorite rum if you can’t find it. Just make sure to use one that’s not overwhelmingly sweet.
Finally, simple syrup is extremely easy to make. You just combine equal parts sugar and water in a small sauce pan and stir them together over high heat until the mixture comes to a boil and the sugar melts, 2-3 minutes. You can make as much as you want and keep it in the fridge for up to a month in a sealed container.
I hope this post inspires you to use more bitters in your cocktails!
Rum Old Fashioned

Ingredients
- ½ oz simple syrup
- 5 drops Prickly Pear bitters
- 5 drops Regan's orange bitters
- A dash of Angostura bitters
- 2 oz rum
Directions
- Step 1 Mix all the ingredients in an Old Fashioned glass. You can add a large ice cube if desired.
- Step 2 Cut a large slice of orange peel (I used a blood orange) and twist it over the drink to release the oils. Use it to garnish and serve.
I am soooo pinning this to make for our next cocktail evening…and I wish is was today LOL. Love the simplicity and elegance of this cocktail, and I’m a huge fan of rum. Thanks for sharing! Just pinned! 🙂
Thank you for pinning it Traci! It’s one of my favorite cocktails, so I hope you like it!
Now this looks like a great drink for a Friday night, enjoying a chat on the patio. I do have rum and bitters in the house. Time to give this a try…and thanks for sharing.
I hope you like it, Gloria!
Bourbon old fashioned is the type my husband enjoys, but I think it’s time to change it up and give this rum version a try! I didn’t realize there are so many different flavors of bitters. Delicious cocktail!
Thank you, Sandra!
I love your brief history on bitters! I remember seeing some Angostura bitters at the store once and even bought it, but didn’t know what it was for haha. The Prickly Pear bitters sound amazing, I’ll have to look for some to make this!
Thanks, Sarah! The prickly pear ones are definitely my favorite. They are so versatile!
WOW!This is definitely a cocktail I have to make. Love the addition of the bitters to the drink. You’ve certainly done an excellent job of explaining them. I’ll have to make sure I have the supplies on hand. I know we have the Angostura bitters now for the rest… Thank you for sharing.
My pleasure, Marisa! I hope you like it!
Who knew there were so many different types of bitters? Thanks for the education! On your recommendation, I’ll start wit the pear bitters…the cocktail sounds delish.
Thank you, Debra!
I love Old Fashioneds but I’ve never thought to make one with rum, which is a really cool twist! I also think the idea of Prickly Pear bitters sounds delicious! These are such a fun twist on the classic!
Thank you, Jenni!
I love that you used 3 different kinds of bitters! I always just stick to angostura, but I’m excited to switch it up and try these new ones.
It’s such a simple cocktail, so I feel that the different kinds of bitters add a little something special to it 🙂
Ah! I have those exact bitters in my booze pantry and I never have any idea what to do with them. Haha. Now I do! I’m not the best mixologist, but we have friends who are. I’ll have to pull this out next time they’re here and surprise them 😉
I hope you and your friends like it, Dana!
This is a gorgeous cocktail and one that I would absolutely love to sip. I’ve never had prickly pear bitters, and I absolutely need them in my cocktail cabinet. What a fantastic blend of flavors you’ve paired in this drink. Perfect for a weekend sip outside, sitting around the fire pit. I’m off to order the bitters!
Thanks, Amanda! Prickly pear bitters are really versatile, so they are great investment 🙂