What do you see in these photos? Infection? Sediment?

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ConstantlyAnxious

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After a few months in my basement, I noticed some of my homebrew bottles had stuff floating in them. I've divided the stuff into three categories. I would really appreciate somebody telling me what I'm looking at in each of these!

These bottles were new PET bottles. There was also a white mold (impossible to misidentify) growing on the outside of the bottles where I must have splashed some wort. I'm assuming this is unrelated unless PET is permeable to mold?

1. Ring around the top
Looks like beer has evaporated a little and left a ring of stuff around the top.
UngEefX.jpg


2. Floating on the surface
Couldn't get a good photo. Several bottles in the batch have small patches of stuff floating on the surface.
SwLh7Il.jpg


3. Around the inside of a ridge in the bottle
Every bottle in the batch has a strip of stuff attached to the inside of the bottle around a shallow ridge. Filaments extend from this strip in places into the beer and you can see them floating around as you move the bottle. You can also see in the photo some small bubbles nucleating around a matrix of particles that seem to be emanating from the strip. In some bottles a structure of fine wool-like strands spans almost the full height of the bottle and seems to be anchored to this part of the bottle.
7JkQPYF.jpg

bsT1jZA.jpg
 
I'd say you might have a little something in there other than sacc but it is hard to be sure... As far as I know, PET has low permeability but what we're usually concerned with is O2. What did you use to clean and sanitize your bottles before filling? Have you tasted one?
 
If your bottles were sealed tight, the beer would not have 'shrunk' or evaporated that much.

Nothing looks like an infection to me. Just looks like sediment floating around, but as noted above, I would be concerned about O2 or mold.

Easiest way to tell, open one up and taste it. If it tastes like wet cardboard, its been oxidized.
 
What did you use to clean and sanitize your bottles before filling? Have you tasted one?

Sodium metabisulphite and rinsing with tap water (I have since started using starsan). Haven't tasted one as they don't look that appealing with the various bits floating around in there. Haven't chucked it though.

If your bottles were sealed tight, the beer would not have 'shrunk' or evaporated that much.

Yeah, I can't have done a very good job. Must try harder.

It's mostly the stuff growing in a stripe around the middle of the bottle that's worrying me - the way it's clinging to the side it can only have been something that has grown there rather than something that's just settled there. Also you can see in the first photo bubbles clustered around it, as if it's respiring or something.
 
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I used carbonation tabs that had some malt extract in them and they left a small krausen ring in the neck and some floating bits on the surface.
 
My guess is that you have some wild microbes in there. That does not make it unsafe to drink.

On all your cold-side equipment, use a cleaning solution after use (like OxyClean or PBW) and a no-rinse sanitizer before use (like StarSan).

It's not glamorous, but most of brewing is spent cleaning.
 
The neck and surface stuff looks like krausen and yeast from the fermentation that carbonated the beer.

Perhaps there was more fermentation time needed before bottling or you just had a rather active bottle carbonation.

The lower ring is more questionable. Tendrils of something growing never sounds to good. Hopefully you have just a souring effect going on right now. Open one up and take a sniff. A taste will likely give you a better idea. Could be something pleasantly tart or something that needs to be tossed.

Mold on the exterior is likely exactly what you suspect and a non issue.
 
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