Based on my grandmother’s recipe
20-30 elderflower heads
2-3 lemons (untreated)
2 kg of sugar (my grandmother used to put 3 kg)
1 package citric acid, 10 g (I always forget to buy)
3 liters of cold water
Clean the elderflower heads from all impurities, such as insects, larvae, faded blossom and any remaining leaves. Rinse under cold water and transfer into a large bowl (I had a ceramic 4-liter bowl). Pour over 3 liters of cold water.
Wash the lemons very carefully. Cut them into slices and then in half-moons. Add to the elderflowers. Stir in the citric acid (optional). Place the bowl in the refrigerator for 24 hours or in a cool place, covering it with a piece of gauze or a lid (just to avoid curious insects from visiting).
The next day, place a strainer over another large bowl and line it with 2-3 layers of gauze. Transfer the elderflowers and lemons in it. Make a bundle and squeeze it tight so as to extract the maximum of its juice. Then throw away the bundle. Filter the remaining juice through another piece of gauze, pouring it in the already filtered concentrate.
Then add 2 kg of sugar (or 3 kg as my granny did) in the filtered juice. Stir the time to dissolve it completely. Place the syrup in the refrigerator for another night.
The next day, pour the syrup into clean glass bottles, seal them tight and store in a dry place (or fridge).
When serving, pour about 1 cm of syrup into a glass and fill it up to the top with sprakling or still water.