First, juice and peel the lemon, orange, and lime. It is important that you use organic fruits since the peel of non-organic fruit is usually treated with pesticides and we do not want any of that stuff in our tonic syrup.

Put the juice and peels in a pot along with the water, the dried lemongrass, the dried cinchona bark, the apple vinegar and salt. Bring to a boil and leave the pot boiling for at least 20 minutes.

After 20 minutes, sift the peels, bark and lemongrass out. You can use a regular strainer, or a coffee filter.

Put the remaining liquid without the solids in a clean pot and stir the sugar in, bring to a boil and boil for about a minute.

Fill in a clean glass or bottle and leave to cool.

When cooled down, mix a small amount of the syrup with sparkling water and your favorite gin.

Enjoy!