Bring sugar and water to a boil and cool.
Mix the flower umbels without stems with the lemon slices, the citric acid and the syrup and leave it for 5 to 6 days in a stoneware pot in a cool place with the lid closed.
Next, drain the syrup and bottle it, cork it and let it rest again in a cool place.
Do not discard the elderflowers (for further use see elderflower vinegar or elderflower liqueur).
Spring in the Hallwag, Bern, kitchen,