Hi,
Last June i brewed a sort of "summer pale" (a bit of wheat and oats, simcoe and summer hops, english yeast) that had great success.
My problem is that now, 3 months later, the beer is realy darker like purple-ized. It only affects some bottles, others are OK, and in the affected bottles the yeast slury is realy purple!
Here are some pictures:
Normal color:
Changed color:
Slury:
It doesn't taste like infected, no acidity at all. It is just a little astringeant and hops flavor and aroma are lower than "normal" bottles.
What do you think may cause that??