One key to staying with the low-carb diet — and still enjoy a summer cocktail — is to make your own low-carb tonic. It’s not that hard, it just takes a little patience. You mix ingredients together over heat, simmer for a bit so they can steep together, then drain to make a base, which you mix with seltzer.
Two ingredients will likely need to be ordered online: powdered cinchona bark and granulated citric acid. Cinchona is a species of tree that grows in South America, and is what gives tonic that distinctive quinine flavor. Citric acid helps preserve the base and also gives the flavor some tang. Limes are key, too.
After you simmer for about 20 minutes, you need to strain. It takes a while. We’ve done this with a jelly strainer, and also just with a flour-sack dish towel. Coffee filters are not very effective.
You will notice an orangish-hue to your homemade low-carb tonic. Not to be alarmed. It’s just proof that you’re doing it right.
Homemade Low-Carb Tonic
6 limes
1/4 cup powdered cinchona bark
1/4 cup granulated citric acid
2 teaspoons black peppercorns
2 teaspoons coriander seeds
2 teaspoons fennel seeds
1 teaspoon allspice berries
The zest of 1/2 nutmeg
5 cardamom seeds
4 cups water
1/2 cup sugar (or if you’re hard-core low-carb, use a sugar substitute. We don’t like the taste as much.)
With a paring knife, slice the zest off the limes. Cut the lime flesh into quarters and add both zest and flesh to a medium stockpot or saucepan. Add remaining ingredients. Bring to a boil over medium-high heat, then turn the heat down to medium-low and simmer for about 30 minutes. Turn heat off and let cool to room temperature.
Remove solids with tongs or strain through a sieve. Place remaining liquid into a jelly strainer over a bowl and let strain for up to 24 hours, until the tonic base is an orange-ish clear hue. (Alternatively, set a colander over a bowl and line it with a flour sack dish towel you don’t mind getting stained.)
Measure the liquid. Add enough water to make 4 cups of tonic base. Usually this is around 1 1/2 cups.
To make the low-carb tonic, measure a ratio of 1:5 tonic base to seltzer water. If you take 1 ounce of low-carb tonic water and mix it with 5 ounces of seltzer, that’s enough for two drinks.
Low Carb Gin & Tonics
4 ounces Tanqueray Gin
1 ounce low-carb tonic base, added to 5 ounces seltzer
1/2 lime
Cut the lime into quarters. Fill two tallboys or stemless wine glasses with ice. Add 2 ounces of gin to each drink. Top with 3 ounces of tonic water. Squeeze the lime into the drink, then drop it in. Using a spoon or even the knife you cut the lime with, gently turn the drink over once or twice.
Enjoy!
