Before starting, you'll need to harvest fresh elderflower heads. Just make sure you know how to identify the tree: any mistake could be toxic if not lethal. Stay away from the cone shaped flower heads of the red elder tree...the flowers and berries are poisonous.
"This delicious, effervescent summer drink has a flavor reminiscent of muscatel wine.
-4.5 litres/1 gallon/20 cups water (you may want to use good spring water and not tap water)
-500g/1 1/4 lb sugar
-6-8 fresh elderflower heads
-2 lemons, sliced
30ml/2 tbsp white wine vinegar
1/Heat half the water to just below boiling point and add the sugar. Stir to dissolve, add the rest of the water and leave to cool. Add the remaining ingredients and leave to stand for 24-48 hours. 2/Strain into strong glass bottles and cork tightly. The drink will be ready to serve in about six days."
For more herbal recipes, I recommend the following book: "Herbal Tea Remedies - Tisanes, Cordials and Tonics for Health and Healing" by Jessica Houdret