Bring 2 liters of water to the boil and allow to cool. Squeeze the juice out of the 16 lemons and add to the boiled water together with the citric acid and sugar and stir well. Let stand in an open pot for 3 days and stir from time to time.
Bottling, the syrup is now ready to dilute and drink. It lasts a long time.
I got this recipe from my aunt in South Tyrol and the syrup tastes really very good. We only have this syrup or orange syrup. Then use 14 oranges and 1 lemon, all other ingredients remain the same.