Remove rose petals from the flower head. Pour 1⁄2 l boiling water over the leaves. Add sugar and citric acid. Place a sieve on top so that all petals are covered with water. Cover the rose water and let it steep for 3 days at room temperature.
Pour the brew through a fine sieve. Fill syrup immediately into clean, hot rinsed and tightly sealed bottles. If you are using a beer bottle, rinse it particularly thoroughly so that the beer smell/taste disappears.
Seal the bottles. Store syrup in a cool and dark place.