I believe we’ve done the work to call this the ultimate Gin and Tonic recipe.
After several attempts to make an exceptional homemade tonic syrup – including this famous recipe from Jeffrey Morgenthaler, and this one from Lottie + Doof, via Tony Cecchini and the NYTimes – Keith and I were unsatisfied. In all cases, we liked the tonic, but we didn’t love it. Our biggest complaint – we couldn’t taste the gin.
Gin is divisive, isn’t it. Do you know anyone who’s on the fence about it? People seem to either shrivel in horror or swoon with delight at the mention of it. Those who swoon like the flavor of gin, and why? Because it’s loaded with botanicals – primarily juniper, but look at this list of other essences you might experience.
After each attempt at a homemade version, we would end up back with our favorite store-bought tonic, Fever Tree Naturally Light. It’s light, not in a phony sugar way, but in a less-sugar way – a plus as most store-bought tonics are ridiculously sweet. It’s only slightly bitter, and has a fresh citrus flavor. But it’s also understated, too much so once you’ve tried a homemade version. So it was our muse, but we hoped for something even better.
How to Make Tonic Water
We started the experiment to create our own recipe with 3 criteria:
The syrup had to be delicious, but subtle enough to accentuate, not overpower the gin flavor.
It had to be cold extracted because cooked citrus zest tastes, well, cooked.
It needed to be just barely sweet and pleasantly bitter.
We decided to try 2 versions – both had the basics: cinchona bark (the natural source of quinine), and citric acid (necessary for extraction and helpful for preserving).
The first version had just citrus zest and lemongrass. The second had zest, lemongrass, and other botanicals: cardamom, lavender, allspice.
We filled our jars with filtered water, shook them daily, and allowed them to steep for 72 hours. I firmly believed that the version without the additional botanicals would prevail.
I was wrong, sort of.
Think of vanilla extract. Take in that incredible aroma and you’re tempted to take a swig. Or you were tempted before you tried it straight the first time. On it’s own, the extract is bitter and pungent. But in the proper proportion, added to a sugary or savory recipe, is matchless. Tonic syrup is like that.
You can’t try a couple of syrups straight and determine which is superior. You have to make a proper drink and try them side by side. Work, work, work!
We did our careful taste-testing and were surprised by the result. Both were excellent. Both were missing something. So we took a chance and combined the two. And, Success! Really, the BEST gin and tonic either of us had ever tasted.
What began as rivalry ended in alliance.
Recipe Update: Several people asked about ingredient weights and I finally got around to weighing as I went – because really, there can be a huge difference in size from one citrus fruit to another or between stalks of lemongrass.
I’ve also increased the amount of rich simple syrup based on recommendations (looking at you, Ken Smith 🙂 ), from several people who commented on the original post – it still only comes out to be 1 1/2 teaspoons of sugar per drink and really does make for a smoother, more balanced flavor. However, if you prefer your tonic more tart / bitter, stick with the original amount of syrup: 2 cups sugar and 1 cup water.
Homemade Tonic Water for the Ultimate Gin and Tonic
- 3 cups water (675 ml)
- ¼ cup chopped cinchona bark (1 ounce / 28 grams)
- ¼ cup citric acid (2.2 ounces / 62 grams)
- 3 limes peeled zests only (0.4 ounce / 11 grams)
- 3 lemons peeled zests only (0.5 ounce / 14 grams)
- 2 oranges peeled zests only (0.5 ounce / 14 grams)
- 3 stalks lemongrass tops and bottoms trimmed and outer leaves removed then sliced into 1/8" to 1/4" rounds (2.5 ounces / 71 grams)
- 4 whole allspice berries
- 3 whole green cardamom pods
- 1 tablespoon lavender
- ¼ teaspoon kosher salt
Rich Simple Syrup
- 3 cups natural cane sugar (21 ounces / 600 grams)
- 1 1/2 cups water (355 ml)
You'll also need:
- Lime wedges
- Sparkling water
Combine all ingredients except rich simple syrup in a sterilized, one-quart lidded glass jar. Shake to combine. Refrigerate 72 hours, shaking occasionally, at least once per day.
Make rich simple syrup: dissolve 3 cups sugar in 1 1/2 cups water over medium heat until sugar is completely dissolved. Allow to cool. Transfer to a container and refrigerate.
After 72 hours, strain tonic mixture into a large glass pitcher. Strain tonic a second time, using a coffee filter or very fine cheesecloth.
Whisk simple syrup into tonic until thoroughly combined.
Pour tonic syrup through a funnel into storage bottles and store in the refrigerator.
For the Ultimate Gin & Tonic
Fill a highball glass with ice. Add 1 tablespoon tonic syrup, 2 ounces gin, and 2 ounces sparkling water. Stir to combine. Serve with a lime wedge (about 1/6 of a fresh lime). To drink: squeeze the lime wedge into the drink, then drop it in. Enjoy!
Carefully wash citrus fruits and lemongrass before zesting / chopping.