I had some other things come up in my schedule and my nice Sierra Madre Pale Ale extract kit sat in my secondary for 5 months after a good primary and good final gravity. Much of the yeast came to the surface eventually and held together in little white clumps which some call yeast rafts (
http://www.homebrewtalk.com/showthread.php?t=227052) (apparently from certain ale yeasts rising up with Co2 per the Handbook of Brewing 2nd ed. p501), which from several other posts I understand is normal. However, I now see the breakdown of those clumps and they have begun to turn blackish gray on the surface, but nothing is fuzzy or hairy. Worst of all, I realized my floater airlock has now dried out sometime in the last month and I fear the yeast turning color is due to oxidation.
Should I bottle the batch? or ditch it?
Do I try to siphon off the black/white off the top first? Or leave it?
Do I stir the top layer back into the beer now to get more yeast suspension, or just siphon out of the middle and dump the bottom inch and top inch in the secondary?
Please advise only if you have seen this before. No guessing unless you are fairly certain please. And thanks in advance for your responses.
Here is a new photo I just took.
http://imgur.com/ohZhRYM