I have, with great sucess, used Hugh Fearnley Whittingstall's recipe: Elderflower champagne recipe - Channel4 - 4Food
I followed the recipe, exept I used about 30 % more elderflower heads. I also added a couple of tablespoons of honey.
On two occasions I made it without adding yeast, and once I added some ale yeast. The batch with added yeast was drier and stronger in ABV, which some people preferred.
