Elderflower Champagne

1. Put the hot water and sugar into a large container (a spotlessly clean bucket is good) and stir until the sugar dissolves, then top up with cold water so you have 6 l of liquid in total. 2. Add the lemon juice and zest, the vinegar and the flower heads and stir gently. 3. Cover with clean muslin, and leave to ferment in a cool airy place for a couple of days. Take a look at the brew at this point, and if it's not becoming a little foamy and obviously beginning to ferment, add a pinch of yeast. 4. Leave the mixture to ferment, again covered with muslin, for a further four days. Strain the liquid through a a sieve limed with muslin and decant into sterilised strong glass bottles with champagne stoppers (available from home-brewing suppliers). 5.Seal and leave to ferment in the bottles for at least a week before serving chilled. The champagne should keep in the bottles for several months. Store in a cool, dry place.