Place sugar, water, passionfruit pulp and citric acid in a medium saucepan over medium heat and stir until sugar is dissolved. Bring to the boil, remove from the heat and allow to cool. Store in the fridge for up to 4 weeks. To serve, pour over crushed ice and top up with water or soda water to taste. Makes 5 cups.
+ Citric acid is a natural preservative and is found in the baking aisle of most supermarkets.