I went out of town while my last brew was in the secondary. When I got home, my wife mentioned that she thought she saw mold floating on top. Naturally, I ran as quickly as possible to make sure that she was wrong. There was no mold, however there was something that looked odd to me. On the bottom of the fermenter, there was a little brownish layer of yeast and then a much larger layer that was green. I have never seen the green layer before and have no idea what it could be, any help would be much appreciated!