Tonic Syrup: What It Is and How to Use It

Tonic syrup is tonic water without the water. It's a concentrated syrup made from cinchona bark (the natural source of quinine), citrus, botanicals, and a little sugar. You mix 1 ounce with about 5 ounces of sparkling water and you have fresh tonic, fizzy to the last sip, with a lot more flavor than most bottled tonic water.

Here's what tonic syrup is, how it compares to tonic water, how to use it in a gin and tonic, a spritz, or a mocktail, and what to look for when you buy one.

What Is Tonic Syrup?

Tonic syrup is the flavor part of tonic water, bottled on its own. The bubbles are left out, so you add them yourself with soda water, seltzer, or sparkling wine.

That one change solves the two biggest problems with bottled tonic. It never goes flat, because the carbonation comes from whatever you pour in fresh. And you control the strength. Use a little less syrup for a light, dry drink or a little more for something bolder.

A good tonic syrup is built from:

• Cinchona bark. The bark of the cinchona tree is where quinine comes from, and it gives tonic its bitter backbone.
• Citrus. Lemon, lime, orange, and grapefruit juice or peel for brightness.
• Botanicals. Common ones include lemongrass, allspice, and warm spices.
• Sugar. Usually cane sugar, to balance the bitterness.
• Citric acid. For tartness and to keep the syrup stable.

Tonic Syrup vs. Tonic Water

	Bottled Tonic Water	Tonic Syrup
Ready to drink	Yes	Add sparkling water first
After opening	Goes flat within a day	Keeps for months in the fridge
Sugar	Often 20 to 30+ grams per serving	Depends on the brand. Jo's is 6 grams per drink
Strength	Fixed	You choose the ratio
Uses	Mostly gin and tonics	G&Ts, spritzes, mocktails, and other tonic cocktails

The tradeoff is one extra step. Bottled tonic is grab and pour. Tonic syrup takes about 30 seconds more. If you care about your gin and tonic, it's worth it. For a deeper look at the bubbles side, see tonic water vs. club soda and how much sugar is in tonic water.

How to Use Tonic Syrup

The basic ratio is 1 part tonic syrup to 5 parts everything else. One ounce of syrup plus five ounces of liquid makes one drink. From there, adjust to taste.

• Gin and tonic: 1 oz tonic syrup, 2 oz gin, 3 oz soda water.
• Tonic water on its own: 1 oz tonic syrup, 5 oz soda water.
• Spritz: 1 oz tonic syrup, 3 oz Prosecco, 2 oz soda water.

Add the syrup and spirit to the glass first and give them a stir, then top with the sparkling water. If you pour the syrup on top, it sinks to the bottom and the drink tastes uneven. Stir gently after topping so you don't knock out the bubbles.

Tonic Syrup Cocktail Recipes

Classic Gin and Tonic

• 1 oz Jo's Original tonic syrup
• 2 oz gin
• 3 oz soda water
• Lime wheel

1. Fill a highball glass with ice.
2. Add the tonic syrup and gin and stir.
3. Top with soda water, stir gently, and garnish with lime.

A London dry gin is the classic pick. Our guide to the best gin for a gin and tonic has more options, and gin and tonic garnishes covers what to put on top.

Orange Fennel Spritz

• 1 oz Jo's Orange Fennel tonic syrup
• 3 oz dry Prosecco
• 2 oz soda water
• Orange slice

Build it in a wine glass over ice, stir gently, and garnish with orange. The syrup brings the bitter-sweet balance on its own, so you don't need a bitter liqueur.

Tonic Mocktail

1 oz tonic syrup, 5 oz soda water, ice, and a squeeze of lime. It's a real drink for anyone skipping alcohol, not just sparkling water with a garnish. For more ideas, see our easy mocktail recipes.

More Tonic Cocktails

Tonic syrup works with almost any spirit. Try a vodka tonic, a tequila and tonic, a rum and tonic, or an espresso tonic.

Can You Make Tonic Syrup at Home?

Yes. Homemade tonic syrup is usually made by simmering cut cinchona bark with citrus peel and juice, lemongrass, and spices, then straining it and sweetening it with cane sugar and citric acid. The bark leaves a lot of fine sediment, so most recipes strain it through a coffee filter, sometimes more than once.

Be careful with it. Quinine in large amounts can cause cinchonism, which brings ringing ears, headache, and nausea. Stick to a tested recipe that uses cut bark, not quinine powder, and measure exactly. If you just want a good gin and tonic, a store-bought tonic syrup is the easier route.

What to Look for in a Tonic Syrup

• Real cinchona bark. It gives a rounder, more natural bitterness than added quinine flavor.
• Real citrus. Juice and peel taste brighter than citrus flavoring.
• Sugar per drink. Tonic syrups range widely. Check the label if you're watching sugar.
• A flavor that fits how you drink. Some syrups are classic and quinine-forward. Others lean citrus, floral, or spiced.

Jo's Tonics

Jo's Tonics are the botanical tonic syrups we make. If you remember Joanna's from Iowa City, it's the same tonic syrup, now part of the Stu's Kitchen family.

Jo's Original is built on real cinchona bark and four fresh citrus juices: grapefruit, orange, lemon, and lime. It's the one for a clean, bright gin and tonic.

Jo's Orange Fennel pairs fresh orange with warm fennel and cinchona bark. It's made for spritzes, Italian sodas, and non-alcoholic aperitivo drinks like a non-alcoholic Aperol spritz.

Both have 6 grams of real cane sugar per drink and make 16 drinks per bottle.

A Short History of Tonic

Quinine from cinchona bark was the first effective treatment for malaria. British officers in India in the 1800s mixed the bitter powder with soda water and sugar to make it easier to drink, and added gin. That's where the gin and tonic comes from.

Modern tonic water uses very little quinine. The FDA limits it to 83 parts per million, which is why most bottled tonic tastes mostly sweet. Craft tonic syrups brought the bitterness and botanicals back.

Tonic Syrup FAQ

What is the difference between tonic water and tonic syrup?

Tonic water is carbonated and ready to drink. Tonic syrup is the concentrated flavor without the bubbles. You mix it with sparkling water, so it never goes flat and you control the strength.

What do you use tonic syrup for?

Gin and tonics, vodka tonics, spritzes with Prosecco, and non-alcoholic drinks with soda water. Anywhere you'd use tonic water, plus drinks where you want more flavor.

How much tonic syrup do I use?

Start with 1 oz of tonic syrup to 5 oz of other liquid. For a gin and tonic, that's 1 oz syrup, 2 oz gin, and 3 oz soda water.

How long does tonic syrup last?

It depends on the brand, so check the label. Jo's lasts 2 years unopened and 6+ months in the fridge after opening.

Does tonic syrup contain caffeine?

No. Quinine is bitter, but it isn't caffeine. Jo's Tonics are caffeine-free.

Is tonic syrup the same as quinine?

No. Quinine is one compound from cinchona bark. Tonic syrup combines cinchona with citrus, botanicals, and sugar to make a balanced mixer.

What sparkling water should I use?

Any plain, well-carbonated soda water, seltzer, or club soda. Skip heavily mineral waters unless you like that taste.