non-used bottles have mold?

Last night I had an unfortunate find in one of my beer bottles of apfelwein. Mold? I poured the last bit of the bottle into the glass (leaving the trub if any in the bottle), but had little black chunks floating in my glass. Damn, as the other 2 glasses of the bottle were soooo good!

So... I checked the other bottle in the fridge, yep same forming at the bottom. Checked the 12 wine bottles I had of it, nothing forming at the bottom. They were clear and not even a little yeast at the bottom of them. I checked my stash of empty bottles and found 1/2 of them had a ring of mold at the bottom!

Hmm. I did soak them in soap and hot water, de-labeled them, rinsed them, washed again, rinsed, sanitized, and air dried. Once air dried, stored (bottles open) upright in six pack carriers in a corner of my bathroom. My bathroom is big, and the shower in a separate room of the bathroom, bottles stored on opposite side. I can't imagine it being a moisture problem, as only 1/2 the bottles had this crap in them.

I'm wondering what might have happened, if anyone has seen this before or heard of it. Is it worth it to soak them again, rinse, and sanitize? Should I throw the infected bottles away, and is the wine in the beer bottles safe to drink with this at the bottom of some of them?

There are a million possibilities. Presumably you've already considered most of the obvious ones. The fact that only half your bottles were infected doesn't really prove or rule out anything, way too many variables.

It's possible they didn't thoroughly dry (this is always a problem for me). It may also be some kind of sediment, but again, assuming you considered that. I'm also assuming you checked when you washed; sometimes I have crud in the bottle that I missed or is hard to get out.

Even if you did everything right, microorganisms are pretty hardy and can sneak in anywhere. Even a large, well-ventilated bathroom can be a mold heaven, so may not be the best place to store them.

A good homebrew saying has kept me safe many a time: wash after use; sanitize before use. Even a "clean" and sanitized surface can become a bacteria home given enough time and exposure to the elements (if you want to do an experiment, put some starsan on a piece of bread and then leave it outside .

As for this batch, does it have an off taste? If it tastes OK (and you have insurance ) I would drink it. But that's just me.

Please keep us posted if you figure out what it was.

Good luck!

In the immortal words of our great former president Ronald Reagan...."Trust, but Verify".

Always...always...always....visually inspect every bottle before you fill it with your precious beer. Any assumptions about cleanliness will only lead to the odd bottle that gets by and has mold in it. Can you imagine how embarrassing it would have been had you given that bottle to someone to try homebrew for the very first time?

I prefer Oxyclean over soap and water.

To make a few things clear here - I always rinse bottles after a pour. I did wash, rinse, and re-sanitize before bottling the batch, but I did not check the bottles. In fact, I bottled 11 in 16oz beer bottles, drank 6 with no issues in the past week, and on the 7th, the last glass had the mold floating around in it. Only been bottled 2 weeks. My better bottle and bottling bucket went through the same wash/rinse/sanitize/air dry and stored in the same place as the bottles and they look like when I bought them still. I might try soaking everything in oxy clean, rinse/sanitize, and store in the spare room to see if that helps.

As for the batch, no off taste, in fact, getting better over the couple weeks since bottling, despite the bottle having the 'mold'. Yes, I'm glad I didn't give this out (a couple wine bottles but no beer ones).