What eldritch horror lurks beneath my yeast cake?

I racked an ESB off its yeast cake tonight, and when I went to wash out the bucket, I noticed some black rings underneath the cake. The beer itself tastes fantastic (I think it might just be the cleanest, most balanced beer I've made to date), and it was under the cake, so I'm not terribly worried about infection. However, I'm wondering if it's time to retire this bucket. Behold the terrors that lurk beyond the cake, and give me your thoughts.

Weird. They are so perfectly round it seems that they are likely from something you stuck in there. PBW the bucket or maybe even bleach it, if you want to keep using it.

Had to look up 'eldritch' - thanks for expanding my vocabulary!

That's the oddest thing I've ever seen.

Maybe some type of mold?

Other than that I got nuthin!

it kind of looks like bottle caps were sitting in water or sanitizer for too long.

The perfect ring shapes are definitely odd, not to mention they look to be about the same size as the end of your auto-siphon wand. Your gasket isn't wearing down, is it?

drainbamage said:

The perfect ring shapes are definitely odd, not to mention they look to be about the same size as the end of your auto-siphon wand. Your gasket isn't wearing down, is it?

Click to expand...

Thought the same thing. Did you happen to reposition the wand multiple times during transfer? Maybe that's the culprit.

I did have some caps that sat in that bucket for a while. I totally forgot about that. The size of the rings is exactly right, too. Hmm. I had washed the bucket pretty thoroughly between when it had caps and sanitzer and when I used it for a beer. What does metal and acid do when in contact with plastic for a week?

beertroll said:

I did have some caps that sat in that bucket for a while. I totally forgot about that. The size of the rings is exactly right, too. Hmm. I had washed the bucket pretty thoroughly between when it had caps and sanitzer and when I used it for a beer. What does metal and acid do when in contact with plastic for a week?

Click to expand...

it could leave discoloration. if that's the case, I'd do a good soak with Saniclean. chances are it will have absolutely no affect on your beer. if you didn't notice any off flavors in your ESB, it's more than likely not a problem. but if it eases your mind, buckets are pretty cheap.