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Homemade Tonic Syrup for the best Gin and Tonic

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A gin and tonic is a fine drink. It’s tough to beat on a summer day, with its effervescence and its botanical fragrance and its hit of citrus.

Its anti-malarial properties from quinine famously protected the British from malaria in India and Africa, a complicated sort of honor in the way that the project of global empire is complicated (and if you want a fun read about the follies of empire you must pick up J.G. Farrell’s The Siege of Krishnapur).

But big-brand commercial tonic water has declined like the empire it propped up for so many years. It barely contains any quinine anymore.

It’s basically sugar or high fructose corn syrup with some citric acid and the ever ambiguous “flavorings.”

There are several high quality fancy-pants tonics on the market, from Q to Fever Tree to Fentiman’s, and while I like all of them, I rarely have them around because they’re kind of expensive and not always easy to find. Also, I’ve learned, I can do better on my own.

Angelica root, juniper berries, orange, lemons, coriander seed, sugar

Most of the tonic recipes you’ll find floating around the Internet are variations on Jeffrey Morgenthaler’s recipe that he shared in 2008. In his excellent 2014 Bar Book (a resource that all serious cocktail geeks should have in their library) he is critical of that original version:

Even my own first recipe, which was lauded by bartenders and home mixologists all over the Internet and in newspapers, I personally found to be muddy, dirty, earthy, and, quite frankly, a bit tough to drink.

I played around with that version a number of years ago, and while I remember liking it, I also remember feeling it wasn’t quite what I wanted to reach for when I wanted a gin and tonic.

And I take his point about it feeling a bit muddy. In part because if you’re using cinchona powder it’s awfully tough to strain out of a syrup (and if you’re using cut bark, it’s tough to extract much quinine flavor).

Morgenthaler gets around this problem by using first infusing the cinchona powder in vodka (I use Everclear) and then adding the quinine tincture to the syrup with the other botanicals and aromatics.

[Edit: This helps to limit the amount of quinine added to the final beverage. Please don’t be tempted add more. Too much quinine can have serious, dangerous side effects, and this is not intended to be used for medicinal purposes!]

Homemade Tonic Syrup | Blossom to Stem | www.blossomtostem.net

I’ve stolen that solution from him for my homemade tonic syrup. But while he flavors his new version with gentian root, cinnamon, lemon and grapefruit, I’ve learned that I prefer a somewhat different flavor profile.

I love gentian-based amaros like Campari and Suze, but while I think it’s interesting in tonic, I think it might be almost too assertive in its bitterness. I’ve learned that I prefer the somewhat softer, more rounded bitterness of angelica root.

Homemade Tonic Syrup | Blossom to Stem | www.blossomtostem.net

I like some aromatic botanicals and bring in a hint of juniper to echo the gin along with coriander and cardamom. It’s a flavor profile I’ve more or less borrowed from Ransom’s Old Tom Gin (my favorite gin for a Martinez).

And somehow, for me, it’s the right balance of tart, bitter, and aromatic.

It compliments gin and has enough guts to stand up to a punchy juniper-forward London dry style gin but is still soft enough to refrain from overpowering all the nuance in a more subtle gin.

Pouring sparkling water over tonic syrup to make tonic water

I also think this homemade tonic syrup lovely to drink mixed with a little soda water as a grown-up soda on its own.

Making this does require tracking down some fiddly ingredients.

I mean, you probably don’t have quinine powder or angelica root in your pantry and are unlikely to find them at your local grocery store, but the Internet makes them easy to track down. And they’re inexpensive and keep more or less forever.

And then you’ll be all set for your gin and tonics for life.

Homemade Tonic Syrup | Blossom to Stem | www.blossomtostem.net
Yield: 28 ounces

Homemade Tonic Syrup

Homemade Tonic Syrup | Blossom to Stem | www.blossomtostem.net

This homemade tonic syrup makes the best gin and tonics ever. It's inspired by the method Jeffery Morgethaler uses in his in his excellent Bar Book, but the flavor profile is loosely inspired by the aromatics in Ransom Old Tom gin. It's tart from the citrus and citric acid, bitter from the angelica root, and aromatic from the coriander, cardamom, and juniper. It does require tracking down citric acid, which you can probably find at your local grocery store, and also angelica root and cinchona powder, which you can easily order online. The quinine tincture makes more than you'll need and it keeps forever. Be sure to weigh everything with a scale for precision--the volume of roots and peels vary too much for volume measurements to be useful. Ideally, look for organic lemons and oranges for this, but if all you have is conventional wash them with hot water first.

Prep Time 10 minutes
Cook Time 20 minutes
Total Time 30 minutes

Ingredients

Quinine Tincture

  • 6 grams powdered cinchona bark
  • 150 ml Everclear

For the botanicals

  • 20 grams citric acid
  • 20 grams angelica root
  • 30 grams orange peel, peeled with a vegetable peeler
  • 30 grams lemon peel, peeled with a vegetable peeler
  • 8 grams coriander seed
  • 5 grams cardamom pods
  • 5 grams juniper berries
  • 400 grams sugar
  • 500 ml water

Instructions

Make the quinine tincture

  1. Mix the cinchona powder with the Everclear, cover, and let sit overnight. Strain through a coffee filter fitted on your finest mesh strainer (or filter cone) into a container. It might take a while. Then strain again through a second coffee filter to really remove the fine particulate. 

Make the botanical syrup

  1. Add all the ingredients to a medium saucepan. Heat over medium-high heat until it comes to a boil, reduce heat to low and simmer, covered, for 20 minutes. Strain through a mesh strainer and let cool. 
  2. Measure out 45 ml (1 1/2 ounces) of the quinine tincture and mix into the cooled syrup. Keep the rest of the quinine tincture in an airtight container (the tincture will keep indefinitely). Store the syrup in an airtight container in the refrigerator. It should keep for at least 2 weeks.

Nutrition Information:

Yield:

28

Serving Size:

g

Amount Per Serving: Calories: 62Total Fat: 0gSaturated Fat: 0gTrans Fat: 0gUnsaturated Fat: 0gCholesterol: 0mgSodium: 4mgCarbohydrates: 16gFiber: 1gSugar: 15gProtein: 0g

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Kate

Monday 18th of October 2021

Hey Mary, this looks amazing! So, I'm sober and I already do a juniper syrup that I add to mocktails. I just came across your recipe and wondered if I could combine your tonic syrup and my juniper syrup (whole dried juniper, corriander, fennel and cardamom crushed) to make a G&T syrup. Knowing the taste profile of your syrup, what do you think?

Kate

Monday 18th of October 2021

I meant to add that I see you already have most of these in yours, so I was thinking of just upping the punch of the things that are already in mine, if that makes sense!

FRANK MCEVOY

Sunday 7th of March 2021

What is the syrup to water/soda water ratio?

Susan Thompson

Monday 26th of April 2021

@Mary Kasprzak, Can you use another alcohol instead of everclear? Not been able to get hold of it.

Mary Kasprzak

Monday 8th of March 2021

It's up to you to adjust to taste. Start with 1:8 syrup to soda water and adjust from there.

Jef

Tuesday 9th of February 2021

I discovered your tonic recipe last March, right around the beginning of COVID quarantine. I explored the other recipes noted here but yours felt like the most balanced, "tasteful" approach. After many delicious batches made and compliments received (and now given backatcha!), I am now considering adjusting it to accomplish something new for me - a non-alcoholic G&T. I have tried N/A gins like Seedlip and Ritual, but instead of this I'd like to try to merge the gin attributes into this tonic recipe. Maybe increase the juniper, add some black peppercorns and rosemary to get that gin profile in a clean, healthy, dry drink. Open to suggestions and ideas. Challenge on....?!

David McKenzie

Friday 25th of December 2020

This recipe sounds very interesting! I have procured all the ingredients but now wondering if the junipers, cardamom and coriander seeds should be lightly crushed before simmering in the water/sugar syrup?

David McKenzie

Sunday 27th of December 2020

@Mary Kasprzak, Thanks for your reply so quickly to an old post! I made my first batch. It wasn't at all like commercial tonic. And I love it! I am partial to Hendricks and Fever Tree with a slice of cucumber. I don't think this recipe would work with Hendricks due to the citrus driven flavours. Have you thought about another recipe that caters for that type of gin. And just because I am down under, I also enjoy a G&T made with Four Pillars gin - but not with regular tonic - it definitely needs a Mediterranean fever tree type tonic. So I guess one with rosmary could work? I'd love to hear your thoughts. D

Mary Kasprzak

Saturday 26th of December 2020

You could do that and it wouldn't hurt anything, but it isn't really necessary. The steep time allows the flavors to come through.

Joni Kämppä

Monday 3rd of August 2020

Is the amount of tincture (45ml) correct? It sounds awful lot of alcohol on the syrup itself, especially if you use strong alcohol like Everclear. Making this right now and concerned about the measurements.

Mary Kasprzak

Tuesday 4th of August 2020

It's correct.

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