Dad's Elderflower Cordial
For roughly 2 1/2 liters of cordial:
30 large clusters of elderflowers
3 large lemons
1,5 liters of water
1500 g sugar
50 g citric acid
Put the elderflowers in a very large container, it should at least hold five liters. Dad uses a metal bucket. Brush the lemons in hot water and thinly slice them. Add to the flowers. Bring the water to a boil, and stir in the sugar and citric acid. Pour this hot liquid over the flowers and lemons. Cover with a lid of some sort. Let the cordial stand in a cool place for 3-4 days.
Strain the cordial, and put into small, freezable containers. If you're not going to use up the cordial any time soon, it keeps best in the freezer. If you don't want to freeze it, you need more sugar and some sort of preservative.