During the summer i decided to give HFW's elderflower champagne recipe a shot. Using Champagne yeast, bottled water, 80 elderflower heads, citric acid, sugar and (as it would seem unfortunatly) white wine vinager. I left to ferment, strained then bottle 20 litres into the pet bottles that the water came out of. So far so good. However some months down the line when i come to test the brew i have 20 litres of wonderly perfumed, effervecent vinegar flavoured champagne. Is it the vinegar in the recipe that spoils the brew or have i introduced some kind of spoilage during the production? Does anyone have any ideas what i can do to bring this back to drinkable? i'm loath to chuck it knowing that it'd be next july before i could try again.
Any ideas would be welcomed at this stage

Cheers