How to make your own tonic water

Although gin might seem like the drink of choice at the moment, it would be nothing without a good tonic water. Learn how to make your own, with my guide.

Here at delicious. HQ we often have cocktails on Friday afternoon (bosses: try it, it works wonders for morale).

This Friday it’s gonna be gin and tonic. Not just any gin and tonic, though. We’re using my homemade tonic water – or, to be precise, homemade tonic syrup, topped up with soda water.

You may be wondering why anyone would want to bother making their own tonic water when they can just buy it.

I can guarantee you there’s no saccharine or unnamed ‘flavourings’ in it. And I’ve wanted to make it ever since I visited the 214 Bermondsey gin bar near our offices and tried their highly flavoursome concoction.

At first I assumed making tonic would be difficult and complicated, well beyond my abilities. In fact it’s one of the simplest things I’ve ever made, hardly more complicated than a properly brewed pot of tea.

That said, getting the ingredients requires a bit of online research – you won’t find citric acid or cinchona bark next to the boxes of Tetley in the corner shop.

Citric acid is readily available online – I bought a 250g bag for just £1.90 on Ebay, including delivery, and you only need 6.5g per batch for this recipe. Should last a while. Just make sure it’s described as ‘food grade’.

More expensive and not so readily available is the cinchona bark. What the hell is that? I hear you ask. The cinchona tree is indigenous to the Andes and its bark has been used for hundreds of years to treat malaria. Have a good Google and you’ll find some. The key is you want it cut, not powdered.

The existence of gin and tonic is thanks to cinchona bark. The Brits grew the trees in their colonies in India, Asia and Africa. To help the daily dose of the extremely bitter extracted quinine go down, so the story goes, they added sugar, lemon juice and gin.

There are lots of recipes for tonic syrup online. As far as I can gather, it all started in 2008 with a recipe from Jeffrey Morgenthaler in Portland, Oregon, the USA’s most hipster-ish city, where doing stuff like making your own tonic water is hardly worth talking about, it’s so commonplace. Over there, they’ve probably moved on to growing the cinchona trees in their gardens.

The recipes often call for citrus zest and/or juice, lemongrass, allspice, lavender… Did I really need all that stuff in my tonic, I wondered. After all, isn’t that what the botanicals in the gin are for? And I always have a wedge of lemon or lime in it anyway.

Kevin's syrup has just four ingredients (just like good beer and bread, those staples of life, each have four ingredients)

Then I came across Kevin Liu, who instantly became my tonic hero. Kevin came up with the innovation of using bits of bark rather than powdered bark, because they’re easier to filter out, and he eschews citrus and other additions, at least for your first few batches.

Kevin’s syrup has just four ingredients (just like good beer and bread, those staples of life, each have four ingredients), which appeals to my belief in purity and simplicity – not to mention my inherent laziness.

As you’ll have noticed, the resulting tonic is a bit yellow in the syrup form (from the cinchona) but it pours a pleasant golden-champagne colour when diluted. It’s robustly bitter with a sweet undertone and herbal flavours.


How will it go down at work on Friday? Quite well, I suspect. Besides, they can’t really complain when it’s free…

Simple homemade tonic syrup
Here’s Kevin Liu’s recipe, translated into UK measurements, rewritten in my English English and slightly amended/adapted. It makes about 500ml, enough for 20 large G&Ts using the G&T recipe below. It should keep in the fridge for a few weeks.

40g cut (not powdered) cinchona bark
360g cold water
220g caster sugar
6.5g (about ½ tbsp) citric acid

1. Put the bark in a saucepan, add the water, then bring to the boil. Turn off the heat, put the lid on the pan and leave for 20 minutes.
2. Strain the liquid into a jug through a muslin cloth (I used 3 layers of unused
J cloth).
3. Add the sugar and citric acid. Stir, leave to cool, then pour into a sterilised bottle or bottles. Yes, it’s really that simple.

Gin and tonic using the simple homemade tonic syrup
Kevin’s recommended proportions for a G&T seem to work a treat. Again, I’ve adjusted his amounts for standard UK measures. If you have a SodaStream, you could of course make your own soda water.

25ml tonic water syrup
50ml gin
75ml soda water
Lemon or lime wedge

Put ice in a glass, add the syrup, gin and soda water, then give it a good stir.

Squeeze in a little juice from the citrus wedge, then add the wedge and enjoy.

Now that’s what I call a G&T.