Wash elderflower umbels carefully. Wash lemons as well and cut into slices. Mix 7 litres of water, citric and tartaric acid. Add the elderberry blossoms and lemon slices and leave to stand for 2 days.
Stir in sugar and leave to stand for another 2 days. Pour through a sieve, bring to the boil briefly once and pour into clean bottles while hot. If stored in a cool and dark place (cellar) the juice will keep for about 3 months. To serve, put it well chilled in a punch bowl and fill up with ice-cold mineral water.
Per liter of juice approx. 2180 kJ/ 520 kcal. E: 1 g, F: 1 g, KH: 1000 g