Homemade Tonic Syrup

By Sina Torner / Last updated on March 21, 2023

Making your own tonic water is a clever way to create the perfect match for your favorite Gin. We're showing you how you can make an amazing homemade tonic syrup.
Jar of Homemade Tonic syrup with ingredients in the background

Tonic water is nothing more than a combination of viscous, bittersweet tonic syrup and carbonated water. We all know the cans or bottles from brands like Fever-Tree, Fentimans, or Schweppes. But you can also make your own version of tonic water at home.

You can find many recipes online, mostly riffs on Morgenthaler's version. Yet, like Morgenthaler himself wasn't satisfied with his initial formula, so weren't we. It's too heavy and sweet - not refined enough to be paired with an excellent Gin.

In a perfect Gin & Tonic, the flavors work together, not camouflage each other. For our recipe, this means that we need something light and not too sweet that underlines or perhaps enhances the taste of the Gin but never overpowers it.

Jump to Recipe | Ingredients | How to Make it | Variations | FAQs


  • Cinchona bark - Chopped cinchona bark is probably the key ingredient. It lends our recipe its distinct bitterness. Additionally, it also brings quinine into our syrup. An integral part of the mixer - homemade or store-bought.
  • Citric acid - This ingredient has two purposes. First, it helps extract the aroma and flavor from other components. Secondly, it helps to preserve the finished product and make it last longer.
  • Citrus fruits - We use various citrus fruits in our recipe. -From lemons to limes to oranges and grapefruits. You only need the peeled zests, though. 
  • Lemongrass - that's part of almost every homemade recipe. It combines a mild citrus flavor with slightly spicy and gingery notes.
  • Spices - Allspice berries, cardamom, lavender, coriander seeds, and some juniper berries add the necessary aroma.
  • (Cane) Sugar, water, salt - To extract the flavors and to make our rich base sweetener, we also need cane sugar, water, and (sea) salt.
Ingredients of Tonic syrup - lemongrass, juniper, lemon peel, orange zest, grapefruit peel, cardamamom, lavender, cinchona bark

How to make tonic syrup

We don't want our final result to be overly sweet and subtle enough to let the flavors of Gin shine through when used in the Gin-based Highball. Further, we wanted to have a fresh citrus taste. That's why we decided on a cold extraction of our flavors.

These are the basic steps you need to follow:

  • 1. Prepare your Ingredients - Wash your citrus fruits, prepare and chop the lemon grass, and measure all your ingredients.
  • 2. Cold extractions - All ingredients are added to a jar with water. The sealed jar goes into the fridge for 72 hours. Occasionally shake it to allow the ingredients to mix properly.
  • 3. Combine with rich simple syrup - After 72 hours, the mixture is ready to be double-strained and combined with a homemade rich syrup. This sweetener consists of two parts cane sugar and one part water. 

That's all it needs. To get homemade tonic water, you only need to mix 1 tbsp of tonic syrup with two ounces of sparkling water. If you prefer a stronger taste, increase the ratio of tonic mixture.

Gin Tonic made with tonic syrup on table


If you want to make a sugar-free version of this recipe, use alternative sweeteners. I don't do that, as the resulting taste is not ideal, but if you're on a diet, that's a way to get that bittersweet flavor with almost zero calories.

I like to make mine with coriander seeds and juniper berries. If you're not a fan, reduce the amounts or skip them. You're taking away complexity, but the result is still tasty.

Adding elderflower to the mix can bring wonderful aroma and flavor. However, don't take this too far. 1/8 to 1/4 of a cup is sufficient to add hints of the floral taste without overpowering the rest of the sweetener.

Jar of Homemade Tonic syrup with ingredients in the background

Homemade Tonic Syrup Recipe

A delicious bittersweet syrup for making homemade tonic water.
Prep Time: 20 minutes
Shaking time5 minutes
Cold-Extraction: 3 days
Course: Syrup
Cuisine: European
Keyword: Tonic syrup
Calories: 26kcal


  • 3 cups Water - (675 ml)
  • 2 oz Cinchona bark, chopped - (56 grams)
  • 2 oz Citric acid - (62 grams)
  • 3 Limes - peeled zests only - (17 grams)
  • 2 Lemons - peeled zests only - (14 grams)
  • 1 Grapefruit - peeled zests only - (10 grams)
  • 1 Orange - peeled zests only - (7 grams)
  • 3 stalks Lemongrass tops, bottoms, and outer leaves removed and then sliced into ⅛" to ¼" rounds - (70 grams)
  • 6 grams Coriander seeds
  • 5 grams Whole allspice berries
  • 4 grams Juniper berries
  • 4 grams Green cardamom pods
  • 1 tbsp Lavender
  • ¼ tsp Sea salt

Rich Syrup

  • 3 cups Cane sugar - (600 grams)
  • 1 cup Water - (355 ml)


  • Combine all ingredients except the ones used for our rich syrup into a jar. Close the jar and shake thoroughly to combine all ingredients.
    3 cups Water, 2 oz Cinchona bark, chopped, 2 oz Citric acid, 3 Limes - peeled zests only, 2 Lemons - peeled zests only, 1 Grapefruit - peeled zests only, 1 Orange - peeled zests only, 3 stalks Lemongrass tops, bottoms, and outer leaves removed and then sliced into ⅛" to ¼" rounds, 6 grams Coriander seeds, 5 grams Whole allspice berries, 4 grams Juniper berries, 4 grams Green cardamom pods, 1 tbsp Lavender, ¼ tsp Sea salt
  • Store in the fridge for 72 hours and occasionally shake the mixture.
  • After 72 hours, strain the mixture through a fine mesh strainer. Next, strain again using cheesecloth or a coffee filter to remove tiny particles.
  • Now, mix 3 cups of cane sugar with 1.5 cups of water in a small saucepan and heat while stirring. Stir until the sugar is dissolved. Then remove it from the heat.
    3 cups Cane sugar, 1 cup Water
  • Combine the mixture and rich cane syrup. Whisk and stir until both components are combined.
  • Use a funnel to pour your homemade tonic syrup into sterilized bottles. Store the final syrup in the fridge.


Serving: 1ozCalories: 26kcalCarbohydrates: 7gProtein: 1gFat: 1gSaturated Fat: 1gSodium: 7mgPotassium: 17mgFiber: 1gSugar: 6gVitamin A: 10IUVitamin C: 3.8mgCalcium: 4.2mgIron: 0.1mg
Tried this recipe?Let us know how it was!

Frequently Asked Questions

How do you make tonic syrup at home?

You make tonic water by combining rich syrup with a cold extraction of ingredients like cinchona bark, lemongrass, citrus fruit peels, and spices.

How do you make tonic?

Tonic water is a combination of flavored syrup made with cinchona bark and carbonated water.

Is tonic syrup the same as tonic water?

No, the syrup is a component of tonic water. To get tonic water, you need to add carbonated water to it.

What is the main ingredient in tonic?

The key ingredient in tonic water is cinchona bark. It's the source of quinine that is responsible for the distinct bitter taste in tonic.

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