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Writer's pictureKevin Kos

Blue Gin & Tonic with DIY Tonic Water!



Hi, Friends of Cocktails. A lot of people love blue cocktails, and many of you said you’d like to see a homemade tonic recipe without quinine. That’s why today we’ll make a Blue Gin & Tonic, using our new DIY tonic syrup without cinchona and quinine - and of course no blue curacao or colored gin.


We’ll add blue spirulina, but that’s optional, so if you just want a plain G&T, just don’t use it. On the other hand, you can’t deny a cocktail like the one we are making today doesn’t look beautiful, plus if you need a drink to enjoy while watching Avatar: The Way of Water, this Blue Gin & Tonic will be perfect. You could say this is the 3rd installment of the Gin & Tonic on Cocktail Time, with the 1st being a basic DIY tonic syrup, and the 2nd one covering over 250 years of the Gin & Tonic evolution.


Still, as we already mentioned you have to be really careful when making homemade tonic syrup with cinchona bark, since the quinine, which is what makes tonic water bitter, can be really dangerous when ingested in high doses. But there’s also another alternative to cinchona bark when making DIY tonic syrup and that’s quassia bark, or quassia amara. This bittering agent will give our tonic water a similar bitter taste, but without quinine. We’ll also need a lot less than when using cinchona bark.


Bark of the Quassia tree, which is native to South America, has been used for centuries in traditional medicine to treat a variety of ailments and is also commonly used as an appetite stimulant. One of the active compounds found in Quassia bark is quassin, which is responsible for its bitter taste and has been shown to have antimalarial, antipyretic, and anti-inflammatory effects. But even with quassia you have to realize things that taste bitter in nature are that way for a specific reason - to ward off predators from eating them.


So keep in mind to use bitter ingredients sparingly, with the knowledge of what and how much you’re using. With that being said, even if you use quassia bark to make tonic syrup, it’s still not recommended for women during pregnancy - and no gin either, of course. Still, quassin is 50 times more bitter than quinine, so the amount we need to make our spring tonic syrup will be firmly on the safe side for most people. So let’s make it, it’s Cocktail Time!



Spring Tonic Syrup

● 150g birch water

● 150g sugar

● 7.5g citric acid

● 3.75g malic acid

● 0.6g elderflower

● 0.7g chamomile

● 2.7g quassia amara


Place all the ingredients inside a bag, vacuum seal the air out and place it in a sous vide bath set at 70°C (160°F) for 1.5 hours. The sous vide gives me the best control over temperature and there’s no evaporation, making it the best technique for this task, just don’t forget to give the bag a few shakes while it infuses to help the syrup dissolve and pick up flavors evenly. If you plan to make the syrup in a pan instead use a lid and a food thermometer, to try and keep the same temperature.


If you are also unsure about what birch water is, it is harvested by drilling a hole into the birch tree trunk and leading the sap into a container, in a similar way you may know from maple trees. The collection period is only about a month per year, at the start of spring when the sap moves intensively,and the wound is then plugged to minimize infection. Birch sap has a somewhat silky texture and is slightly sweet, not unlike coconut water if you need a replacement, although regular water works too.


Once our Syrup is done, place the bag in cold water to cool down before opening. We’ll want to filter out all the small bits so I’m using a rinsed coffee filter. Since quassin is much more bitter than quinine we didn’t have to grind the quassia bark like we did for cinchona bark, which makes adequate filtering easier also. With that, all we have to do is bottle it and it’s ready to be used in our Spring Tonic Water, and I thought it would be fun to make it blue, so I got some blue spirulina.



You know spirulina, that blue-green algae that’s responsible for culinary masterpieces, such as Mermaid Toast, Unicorn Frappuccinos, and the Blue Lagoon Smoothie Bowls. But in all seriousness, this superfood is packed with antioxidants, nutrients, and minerals, and best of all, it doesn’t have that pond-water taste that some people get from green spirulina. Also, instead of using soda water we’ll again use birch water and carbonate everything in a iSi Gourmet Whip.


Also I swear this episode isn’t sponsored by “Big Birch”. Birch water is just something more people should know about - it tastes good and it has tons of benefits like manganese. With that said, let’s make this tonic.


Blue Tonic Water

● 45 mL (1.5oz) Spring Tonic Syrup

● 255mL (8.5oz) Birch Water

● 6 drops Saline Solution

● 0.1g Blue Spirulina


I’m using a small iSi container of about half a liter, so if yours is bigger make sure to double the amounts. Either way, begin by chilling your ingredients and once they are very cold add them to your whipper, and feel free to replace the birch water with coconut or regular water. Close the cream whipper and give everything a shake to mix in the spirulina before adding a CO2 cartridge. Once it’s carbonated give it a shake again and place it in the fridge for a little while before you give it a taste.


Because I went with birch water, it will foam up a bit more than regular water, but pour it slowly and you’ll get to enjoy not just the color but also the familiar tonic aroma and bitter taste, with a pleasant floral addition. It’s great on its own, but like we mentioned a few episodes back, when you find the perfect pairing of tonic & gin it brings both ingredients to a new level. So let’s use this to make a Spring Gin & Tonic.



Blue Gin & Tonic

● 45 mL (1.5oz) Malfy con Limone

● 135mL (4.5oz) Blue Tonic Water

● Primrose Flower


As with the Modern Gin & Tonic in that Old vs New episode, start with a chilled high tumbler glass and a clear ice spear. Then add the gin and top up the glass with our Spring Tonic Water. I’m going with a 3:1 ratio of tonic to gin this time, so the subtle floral notes in the tonic don’t get overpowered by gin’s botanicals. Garnish with a primrose flower, and that's it. Spring is here, friends of cocktails. Cheers.


Due to the gin we used it still has more citrus notes than floral ones on the aroma, but the taste is the perfect balance of the two, with a subtle bitterness on the aftertaste. It’s a lighter, but a truly enjoyable gin & tonic, perfect for the spring. Winter has its cocktails, summer definitely has its cocktails, and so does the fall, but I’d love to know what your go-to spring cocktails are. Share them in the comments of the full episode on YouTube, and get ready as next week I’ll be doing the second installment of 0-proof Cocktail Time, so check out the Alcohol Free Bitters episode in the meantime. I’ll see you then, cheers!



 cocktails, mixology, bartending, super juice, kevin kos

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