Most rum drinks lean sweet. Rum and Coke, rum and pineapple, rum and mango, they all involve mixers that add sweetness on top of the natural sweetness of the spirit. Rum and soda is the opposite: just rum and carbonation, nothing else.

This is how you can really taste the difference between a high-quality rum and a bargain basement bottle.

The grassy sugarcane notes of a white rum, the molasses depth of a dark rum, the vanilla warmth of a spiced rum, all come through without a flavorless mixer. It’s a lighter drink than most rum cocktails, and way fewer calories than a Rum and Sprite or other two-ingredient rum-and-flavored-soda-or-juice cocktail.

Which rum

White rum is the cleanest choice and makes the most refreshing version for summer sipping. The lightness of white rum and the neutrality of soda water make a simple, crisp cocktail.

Dark rum adds richness and depth, with molasses notes coming through more clearly without a sweet mixer muddying them.

Spiced rum leans sweet in the base drink, but works well if you add lime to keep it balanced out.

The sparkling water

Topo Chico is my preference for the same reason it works well in a Ranch Water or a tequila soda: its carbonation is stronger, and its mineral profile adds a subtle note. Club soda is the reliable backup, but it does add sodium bicarbonate, which will give you a little saltiness in your beverage.

Ratio

2 oz rum to 4 oz soda water is all you need. Soda adds nothing sweet, so this runs drier than most rum cocktails. A squeeze of lime at the end adds the brightness that keeps it from tasting too flat.

Garnish

Squeeze a lime wedge and drop it in before serving, and add a mint sprig to enhance the aroma if you want the drink to taste more summery.

Find more ideas in my cocktail garnishes guide.

3-Ingredient Upgrade: Adding Lime

Add half an ounce of fresh lime juice before topping with soda. The citrus adds acidity that balances the sweetness of the rum and gives the drink structure. A mint sprig laid over the ice adds aroma when you inhale before every sip.

Grab a citrus juicer to make the lime fast and fresh, and a long cocktail stirrer to mix the ingredients together without destroying the carbonation.

Mocktail Version

Soda water with fresh lime juice and a mint sprig makes the perfect summer mocktail, at least in my house, since we always have fresh limes on our tree and various types of mint growing in the garden.

If you really want to, you can grab a non-alcoholic rum, which brings back the sugarcane character if you want something closer to the original.

Glassware

Use a highball glass for a longer-lasting cocktail, or a lowball with a big ice cube and a short pour of dark rum and soda for a more spirit-forward version. I keep highball glasses and lowball glasses at home so I never have to think twice about what glass I want to use for which cocktail on any particular day.

Other rum cocktails to try:

• Orange Blossom Mojito
• Pineapple Thyme Punch
• Guava Spritz

More 2-Ingredient Rum Cocktails:

• Dark ’n Stormy
• Rum & Coke
• Rum & Soda
• Rum Guava
• Rum Iced Coffee
• Rum Lemonade
• Rum Mango
• Rum Pineapple
• Rum Sprite
• Rum Tonic
• Rum Watermelon

Rum and Soda

Serves 1

Ingredients

• 2 oz white or dark rum
• 4 oz sparkling water or club soda
• Lime wedge, for garnish

Instructions

1. Fill a highball glass with ice.
2. Add rum.
3. Top with sparkling water and stir gently.
4. Squeeze a lime wedge over the top and drop it in.

Lime Upgrade (3-Ingredient Version)

Ingredients

• 2 oz white or dark rum
• ½ oz fresh lime juice
• 4 oz sparkling water
• Mint sprig and lime wedge, for garnish

Instructions

1. Fill a highball glass with ice.
2. Add rum and lime juice.
3. Top with sparkling water and stir gently.
4. Garnish with a mint sprig and lime wedge.