After a few attempts at making tonic water at home, I like this version the best.
It's not too sweet and uses fresh stevia leaves which could be changed out with stevia liquid or dried leaves, it has plenty of citrus flavour and enough cinchona fllavour (the plant responsible for that recognisable quinine taste).
You can easily swap around the herbs and spices for those that you prefer.
As this is a concentrated recipe, you can dilute it to your taste liking with sparkling water or still water if you prefer.
This recipe makes about 700 millilitres (a little over a pint) and will keep in the refrigerator for up to 5 days.
Depending on your flavour preference and how strong you like your G&T, you can adjust the amount of sparkling soda water and gin to suit yourself.
70ml of tonic water combined with 35ml of gin and approximately 200-250ml of soda water, served over ice and with a slice of fresh lemon in a tall glass.