- Finely zest 4 lemons then juice all the lemons.
- Heat the sugar and water in a large (non-aluminium) pan slowly until all the sugar has dissolved.
- Remove syrup from heat and stir through the lemon zest.
- Dissolve citric and tartaric acid in lemon juice and mix with the syrup.
- Pour cordial into sterilised bottles and refrigerate until needed.
- Serve diluted with water or soda to taste.
Cordial will keep in fridge for 6-8 weeks.