I have stuff floating in the tops of my bottles. Could it be yeast? I bottled the beer 12 days ago but one of my friends bottles had mold in them as he did not wash them after drinking them. We washed all the bottles in a big ice chest B-brite cleaner then sanitized them in a separate bucket with iodine based sanitizer. We also filled my friends bottles last. . I had the beer in the primary for over a week and at least 2 weeks in the secondary. Would mold float or is it yeast?