Boil the water in a large saucepan and allow to cool.
Cut the lemons into slices. Shake out the elderflower umbels a little and add everything to the water. I don`t wash the flowers because the taste is more intense then. Cover everything with a plate or wooden board so that the lemons and the flowers are completely covered with the water, then leave to steep overnight.
Strain the brew through a fine sieve and then mix in the citric acid. Heat the liquid to 85 ° C and fill it airtight into clean bottles. Bottles with swing top are very suitable for this. If stored in a dark and cool place, the juice can be kept for a good year.
The juice can, according to instructions, for. B. can be processed very well into jelly on the preserving sugar. I also often add a dash of the juice to other jams, it refines the aroma.