Slimy roots beer

[onthequercusp]

Hey there ...

I've made a couple of batches of roots beers in the past based on Sandor's recipes (roots tea with sugar, ginger bug, etc.) with great success, but I just sampled a couple of bottles of the newest batch and they're thick and slimy. The two I tried happened to be in reused plastic water bottles and I think they were among the last bottled; I have others in Grolsch bottles which I haven't opened yet. It's pretty disappointing. Perhaps they are drinkable, but it's disconcerting to drink something so slimy and filmy.

They've been fermenting for a couple of weeks in a room that's about 66 degrees F.

Anybody have any ideas on the causes of a thick fermentation? Whence the slime?

Thanks, everybody!