Mold or Pellicle?

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oxilic

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I've brewed a brown ale around 2 weeks ago, it finished fermenting after around 4 days, and afterwards started to release a rotten egg smell, which I just assumed was from the fermentation as I've never used this yeast before (M42).

I've opened the bucket today after another 10 days maturing at a higher temperature and noticed a thin oily layer and some floating white circles.

Picture
Picture

It also smelled acidic / vinegary. I took a sample from under the top layer and it seemed to taste and smell fine though. Should I dump it to not risk drinking weird mycotoxins or just risk making an accidental sour?
 

Falstaff

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I've brewed a brown ale around 2 weeks ago, it finished fermenting after around 4 days, and afterwards started to release a rotten egg smell, which I just assumed was from the fermentation as I've never used this yeast before (M42).

I've opened the bucket today after another 10 days maturing at a higher temperature and noticed a thin oily layer and some floating white circles.

Picture
Picture

It also smelled acidic / vinegary. I took a sample from under the top layer and it seemed to taste and smell fine though. Should I dump it to not risk drinking weird mycotoxins or just risk making an accidental sour?

Looks like CO2 to me...but the smell you report isn't a good sign.

On dumping it, Lacto will make a sour but a vinegar smell comes from aceto. Sorry for the bad news but every time I smelled aceto the beer was worse for it, not better. One of them was an IPA which was barely good enough to drink still, the rest I wish I'd dumped instead of bottling, then dumping and cleaning each bottle.
 

Falstaff

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Just saw the dots in the middle of the bubbles. Looks like it might be the start of a pellicle. From my experience this always comes from oxygen. You can sanitize but you can't sterilize so it's always gonna be there to some degree. Oxygen REALLY makes it take off, and I have some anecdotal evidence that leaving it at high temps might make it worse too, but I'm not sure about that.
 

IslandLizard

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If you've ever smelled a Hefeweizen (or many Lagers and Ciders) fermenting, you'd never drink them. ;)
The white dots could well be yeast rafts, surrounded by outgassing CO2.

Too bad you keep removing the lid, you lose your headspace CO2 quickly, being replaced by air (21% O2). You can easily take samples without opening the lid.

Is it infected? Maybe... But it will definitely get infected leaving it in the bucket for much longer, with all that O2 in the headspace.
If it tastes good, not sour, and your FG is what's expected and stable for a week, I'd bottle it ASAP.

You got a keg, instead of bottling?
 

Falstaff

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If you've ever smelled a Hefeweizen (or many Lagers and Ciders) fermenting, you'd never drink them. ;)
The white dots could well be yeast rafts, surrounded by outgassing CO2.

Too bad you keep removing the lid, you lose your headspace CO2 quickly, being replaced by air (21% O2). You can easily take samples without opening the lid.

Is it infected? Maybe... But it will definitely get infected leaving it in the bucket for much longer, with all that O2 in the headspace.
If it tastes good, not sour, and your FG is what's expected and stable for a week, I'd bottle it ASAP.

You got a keg, instead of bottling?

I wouldn't let it sit any longer either. If the OG was low 10 days was probably enough. The CO2 in the bottles should prevent it from getting worse.
 

hotbeer

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I see stuff like that all the time on my ferments. I just ignore them and bottle. If they ever start tasting so bad I don't wish to drinking the beer, then maybe I'll pay more attention.

You'd probably be all upset at the stuff you'd see if you had a glass carboy to ferment in. Once you see all that, pictures like you show look like nothing.

I don't open my fermenter to peek. So maybe avoid doing that and just go by what the stuff you get out of the spigot tells you.

I will have to admit the vinegary smell sounds suspicious. But if your resulting beer is vinegary, then that malt vinegar on a piece of fried fish might be good eats.


All extract or grain? Hop or other additions?
 

MaxStout

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It also smelled acidic / vinegary. I took a sample from under the top layer and it seemed to taste and smell fine though. Should I dump it to not risk drinking weird mycotoxins or just risk making an accidental sour?

You sure that acidic smell isn't just the CO2 from fermentation? It can give a sharp odor (carbonic acid). You said the beer smells and tastes OK--a good sign.

And quit opening that fermenter so much. Leave it alone until it's ready, or you might infect and/or oxidize it. Let it ferment, then package.
 

Falstaff

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You sure that acidic smell isn't just the CO2 from fermentation? It can give a sharp odor (carbonic acid). You said the beer smells and tastes OK--a good sign.

And quit opening that fermenter so much. Leave it alone until it's ready, or you might infect and/or oxidize it. Let it ferment, then package.

Yeah don't open so much. It's gonna do what it's gonna do. I stopped having infections when I stopped opening them. I also switched back to glass. Buckets breath too much when you open them because they flex, also a narrower neck on glass seems to help.
 

IslandLizard

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I also switched back to glass.
There are serious, even life threatening dangers associated with using large glass containers, such as 5-6.5 gallon glass carboys. We have a thread (compendium) of broken glass carboys containing some horrific images.

Friends of mine had one crack in their apartment's living room, soaking 5 gallons of beer in their carpeting. They're still cleaning and shampooing that area as it remains smelly and sticky. They've already given up on their security deposit...

Especially suspect are glass carboys that were manufactured without decent QC, e.g., the ones coming from China (without any indication of their origin). They can crack unexpectedly due to pour construction; wall thicknesses of less than 1/16" (!) have been found, which is a sheer crime for glass vessels meant to hold 5-6 gallons (42-50 lbs) of liquid in them. Most, if not all of the ones failed were of the "ribbed" variety. Ribbed models are also made in Italy (they should be clearly marked on the bottom) seem to fare much better, but you still need to be very cautious handling them. Use a crate or brew hauler type of strapping when moving and handling them. Never lift or carry them by the metal handle around the neck, if they have one, unless they're empty.

There are plastic (PET) alternatives available, which I would recommend instead of using glass. Or stainless at a (much) higher price, but virtually indestructible, with one caveat, they're not transparent, so you need to pay closer attention when racking.
 

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There are serious, even life threatening dangers associated with using large glass containers, such as 5-6.5 gallon glass carboys. We have a thread (compendium) of broken glass carboys containing some horrific images.

Friends of mine had one crack in their apartment's living room, soaking 5 gallons of beer in their carpeting. They're still cleaning and shampooing that area as it remains smelly and sticky. They've already given up on their security deposit...

Especially suspect are glass carboys that were manufactured without decent QC, e.g., the ones coming from China (without any indication of their origin). They can crack unexpectedly due to pour construction; wall thicknesses of less than 1/16" (!) have been found, which is a sheer crime for glass vessels meant to hold 5-6 gallons (42-50 lbs) of liquid in them. Most, if not all of the ones failed were of the "ribbed" variety. Ribbed models are also made in Italy (they should be clearly marked on the bottom) seem to fare much better, but you still need to be very cautious handling them. Use a crate or brew hauler type of strapping when moving and handling them. Never lift or carry them by the metal handle around the neck, if they have one, unless they're empty.

There are plastic (PET) alternatives available, which I would recommend instead of using glass. Or stainless at a (much) higher price, but virtually indestructible, with one caveat, they're not transparent, so you need to pay closer attention when racking.

It does scare me, I'll say. I work in another... sticky...industry that uses glass carboys for product and I was in the room when one shattered in a coworkers hands while using hot water to clean it. It wasn't pretty.

It worries me when I clean mine but I'm afraid to switch to PET because my old buckets kept getting infections, even with good sanitation. I believe the seals wore out, but I cant afford to replace them all the time. I'll look into steel.

I use the same carboy my father and me used to brew when I was 5yo so idk what the construction is besides that it has ribs.
 

IslandLizard

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It worries me when I clean mine but I'm afraid to switch to PET because my old buckets kept getting infections, even with good sanitation. I believe the seals wore out, but I cant afford to replace them all the time. I'll look into steel.
I still use 6.5 gallon plastic brew buckets I got in 2010. Never had an infection in any of those. The lid, especially the groove, needs serious attention when cleaning and sanitizing, and again, before opening. Opening buckets during fermentation is generally a no-no, anyway, unless you're ready to rack to a bottling bucket or keg.

To prevent opening buckets, I drilled a 1" hole in some of the bucket lids as a 2nd port to stir through or add dry hops and adjuncts. All while streaming CO2 through the airlock hole. Then for good measure, purge/flush with CO2 when putting the stopper and airlock back in.

PET is very smooth, and you want to keep em that way. Don't use anything scratchy, just swirl a soft cloth inside with your cleaner (PBW, Oxiclean) to get just enough friction to clean any leftover haze and grime. When cleaned carefully, then sanitized thoroughly, there's no reason why PET would be more susceptible to infections.

To clean buckets I sometimes use a soft, non-scratching pad (10 for $1 at Dollar Tree) when necessary, although a washcloth is often enough.
 

IslandLizard

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I believe the seals wore out,
The groove and rubber seal themselves may well be the cause of infections. The seal needs to be removed, thoroughly cleaned and sanitized, as well as the groove itself, or crap can hide underneath, in the groove.

[Edits]
My regular 6.5 gallon ROPAK ale buckets don't use/have seals, they seal very well without, i.e., the lid bulges when blowing in CO2.

I also have some 3.5 gallon buckets with screw-on lids that do have an o-ring in the narrow groove. When used as fermenters, the o-ring and groove/channel get cleaned as I outlined above.
 
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Beermeister32

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There are serious, even life threatening dangers associated with using large glass containers, such as 5-6.5 gallon glass carboys. We have a thread (compendium) of broken glass carboys containing some horrific images.
This is great advice, I wish more people would take this seriously. There are a lot of glass carboy holdouts. New glass carboys are so much thinner than the old style thick glass carboys of the past. They really pose a huge danger. I ended up throwing mine in the dumpster and use plastic exclusively. MUCH safer and lighter too, an important consideration when lugging 5.5 gallons of liquid around.
 

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