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Mold in my bottle?

Last night I had a bomber of my batch of Jamal’s Evil Twin (renamed Attacked By Robins), bottled about a month ago. On the inside of the bottle there were a half dozen or so small globs clustered together that looked like - for lack of a better description - black mold.

Can mold form in a bottle while carbing/aging?
Or is it some hop/trub residue that maybe got transferred during bottling?
Bad cleaning/sani job by me?

On the upside, the beer tasted amazing, probably the second best thing I’ve made so far (right behind Dead Ringer). I had tried my Jamal’s Evil Twin early on (10 days in bottle) and it didn’t wow me, but as it’s aged another couple of weeks the difference is night and day. And whatever mold or gunk was in the bottle sure didn’t impact the taste…


Most likely it is mold that was stuck in the bottom of a particular bottle and worked its way loose after bottling.

I have had this happen when I give someone else some beer and tell them to save the bottles. I took a cooler of homebrew to a childs birthday party recently and left it there for my friend to finish off. He gave me the cooler back with all the empties in it. He didn’t bother rinsing them out and of course sitting in the cooler they produced mold inside each bottle. I ended up putting all those bottles in the recycling bucket as I didn’t want to deal with them.

Sad too because most of them were big bottles. Bombers and whatever those big DogfishHead bottles are. Just didn’t want to chance it/worry about cleaning them.

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