Homemade Tonic with a Sous Vide Twist
By: Steven Rodia
Some of the new boutique tonics on the market are very tasty, but they can also be very expensive. One of my favorites happens to be a concentrate that you need to dilute with club soda. What I’ve included below is an adapted version of a recipe that I first read about on Jeffrey Morgenthaler’s blog. I lowered the level of cinchona bark in a effort to avoid any toxicity concerns. The end result is a delicious tonic concentrate that you can add to your favorite tonic-based cocktail. I utilized the Nomiku sous vide device to slow the flavor extraction process down and try to capture more of the essential citrus oils without the scorched taste you get when simmering or boiling the mixture with the solids. The cinchona bark and citric acid can sometimes be hard to find locally if you don’t have an herbalist or specialty store. I ordered my ingredients from Herbal Advantage on Amazon.com.
Tonic Water Recipe:
- 4 cups of fresh water
- 4 teaspoons of powdered cinchona bark
- 1 cup of lemongrass – rough chop
- 1 lemon, zest added and juiced
- 1 lime, zest added and juiced
- 1 orange, zest added and juiced
- 1 grapefruit, zest added and juiced
- 1 teaspoon of allspice berries
- 1/4 cup of powdered citric acid
- 1 tsp of salt
- 3/4 cup of agave syrup
One note of caution: As with any ingredient, there is a level of toxicity concern if you use too much cinchona bark. Please see the linked article for additional details.
Place all of the ingredients in a large plastic bag and seal using the displacement method (video here) or by using a vacuum sealer. Add the bag of liquid to the water bath with your immersion circulator device* set for 70°C (158°F) and cook sous vide for 2 hours. Remove the bag from the water bath and strain through a standard coffee filter until all of the major solids, zest, and the majority of the powdered cinchona bark have been removed. It took me several times to get to a liquid that would flow freely through the filter without clogging or leaving large amounts of residue. When you’re happy with the clarity of your tonic concentrate, add the agave syrup slowly while stirring. Adjust the sweetness to your taste. You will want to keep your newly made tonic in the fridge and it can be enjoyed for up to two weeks. As you make consecutive batches, you can experiment with other botanicals to see how they change the resulting tonic flavor. I like adding some dried Valencia Orange peel and a little ginger to the recipe, but experiment and see what taste suits your palate best. Top the tonic with some club soda when creating your favorite tonic-based cocktail.
* If you’re making this recipe without an immersion circulator, combine the ingredients in a pot, cover with lid, and bring to a boil. Reduce to a simmer for 20 minutes and remove from heat. Once the liquid cools, follow the instructions above starting with the filtering process.
Cocktail Idea – Bourbon, Lemon, and Tonic (BLT):
As Spring approaches, there’s nothing better than a nice citrus-based cocktail for the nice evenings outdoors. This concoction is near the top of my list. It combines sweet and sour with with caramel and vanilla notes of the bourbon whiskey to make the perfect sipping cocktail.
- Add 2oz of your favorite bourbon to an old-fashioned or rocks glass
- Add the juice from one Meyer lemon (standard lemons work fine, but Meyers have a nice sweet and sour taste that works well with this cocktail)
- Pour in 1oz of your fresh tonic concentrate
- Top with some fresh crushed ice (or your favorite ice sphere) and some club soda and stir until combined
- Express the oil from a Meyer lemon peel onto the rim of the glass and place the peel into the cocktail