I’ve been working on making some improvements to the gin and tonic recipe in liquid intelligence. The recipe in liquid intelligence is very delicious but it’s a little bit impractical to make the best version since you need to clarify lime juice for it and either extract quinine from cinchona bark or buy medical grade quinine sulphate to make a tonic syrup.

Dave Arnold recommends making a cinchona syrup by boiling ground up cinchona bark in water for a few minutes and then making a syrup with the extracted quinine. I had an idea to try and use vodka instead to extract the quinine since quinine is much more soluble in alcohol than water. My method is to steep the cinchona bark in vodka for a while. Tasting this I can confirm that quinine dissolves much more readily in alcohol than water. According to my googling, about 2 shots of this quinine solution would be the maximum recommended daily dose, if you assume that the vodka is completely saturated with quinine. In my recipe I use about 0.5g-1g of the infused vodka which I deem to be a safe amount. If you make this be sure to consider the risks of ingesting too much quinine. I then filter and decant the mixture into a spray bottle which I can then use to precisely dose the drinks with the cinchona infused vodka.

I actually think this method is safer than grinding up cinchona bark and then making the syrup (as per liquid intelligence) because there is less of a chance of getting chunks of cinchona bark in the finished drink.

Since you only need 11.5ml of clarified lime juice per gin and tonic, it’s a impractical to make a batch of agar clarified lime juice for a couple of drinks, and because the lime juice doesn’t keep. To get around this I use the super juice recipe by Kevin Kos which I then Agar clarify. This allows me to make a big batch of juice which I can then freeze without too much of an impact on taste. Pure lime juice doesn’t taste good after freezing. One thing that I have been meaning to try is to clarify the juice using freeze-thaw agar clarification since the time it takes is no longer an issue, rather than just using the quick agar clarification.

So the recipe is as follows:

1. Make cinchona infusion by steeping cinchona bark in vodka for a day or so.
2. Make super juice with limes (or a mixture of lemon and limes / other acid adjusted citrus depending on the gin). Then agar clarify using either freeze thaw or quick agar clarification. If you plan on leaving this in the freezer for a long time, consider not adding in the juice from the citrus into the batch of super juice.
3. Mix drink to taste – this is the recipe from Liquid Intelligence:
   1. 12.5ml simple syrup,
   2. 11.5g clarified lime super juice
   3. 53ml gin
   4. 87ml water
   5. 0.5-1g of Cinchona infused Vodka
4. Chill and carbonate.