Wort turned black within 5 minutes

Ingredients
1

I am writing to ask what made this happen.  Admittedly I am new to brewing, as this is my 4th batch, but I have never heard of this happening.

I brewed an Belgian Imperial IPA.  The temperature in the carboy was a little warmer than I wanted at 74*, so I thought I would wait to pitch the yeast till it dropped.  In the meantime I went ahead and aerated with pure O2 for 60 seconds.  About 5 minutes later I looked at the carboy and the wort was almost totally black!

I assumed it was because of the O2, so I immediately pitched the yeast (since it is OK up to 76*).  It has since cleared back up to it’s approximately 9 SRM.

But this is a puzzle.  What happened?

Steve

2

I heard of this happening but can’t remember the forum I read it on. Try searching for it.

3

Probably just the trub that was in there dropping out.  It didn’t have anything to do with the O2.

4

Found it! http://www.homebrewersassociation.org/forum/index.php?topic=13315

5

Well I could see this if it was just darkened, but this was black.  And then it turned back to its normal orangeish yellow shortly after.

Also I did do a search but it just referred to a post fermentation and permanent blackening.

Steve

6

What do you use as a sanitizer?

7

Starsan

8

Hmmm… I thought maybe if you used iodine-based sanitizer you were just getting a starch rxn.
Could me just the trub settling and reflecting more less light, thus making it seem darker.
Let it sit and see what happens perhaps?

9

Like I said above, a little darkening wouldn’t be remarkable–turning black was.  Well it is in the fermentation kegerator now, looking like it should.  Hopefully it was just a weird fluke and nothing will come of it.

Steve