did a batch of ginger beer using the hugh fearnley-whittingstall recipe of his site, came out well, very tasty, however not very boozy, so I tried again! this time I did it in a Demi John with an airlock, (also I added a little yeast nutrient) I had to keep letting the pressure off before so I figured if I was to brew it for longer this would be best, the recipe was 48 hrs brewing, I decided to give it 4/5 days to get it a bit more boozy, it was all going ok and it was bubbling away like mad when it slowed down this morning when I checked on it, I decided to bottle up tonight, I got home and it had totally stopped bubbling so I bottled it and had a taste, not good! taste likes vinegar! can anyone tell me what went wrong and what I did wrong? thanks Gregor.