Source fresh market fruit where possible. It will give better flavour and more juice than supermarket alternatives. Scrub all citrus thoroughly regardless of source.

Zest all the citrus before juicing, taking just the coloured outer layer and avoiding the white pith which turns bitter. Add the zest to a heatproof bowl or large jug.

Combine the sugar and water in a saucepan over medium heat, stirring until the sugar fully dissolves. Do not boil, you're aiming for a clear, hot syrup at around 80 to 90°C. Pour the hot syrup over the zest and stir in the citric acid. Cover and leave to steep for one hour.

While the syrup steeps, juice all the citrus. Strain out any pips and large pieces of pulp.

Once the syrup has fully cooled, stir in all the fresh juice. Rest for 15 minutes then strain through a fine mesh sieve, pressing the zest gently to extract all the flavour.

Sterilise your bottles with boiling water and leave to drain completely. Pour the cordial into the sterilised bottles and seal tightly. Refrigerate once opened. Keeps for 3 to 4 weeks in the fridge.