Wash the elderflowers carefully.
Boil the water with the sugar and let it cool down a bit.
Add the elderflowers and the citric acid to the sugar water.
Leave to infuse for 3 days in a dark, cool place.
Then fill the mixture with grain schnapps, stir well and leave to infuse again for a few days.
Empty the elderflower liqueur through a sieve and then fill into bottles.