Acetone Off Flavour

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Acasta

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Just kegged a batch, and when I went to clean the fermenter I got a really strong nail polish remover/Acetone smell coming from it.
I've done a bit of research and most people are claiming the cause to be non-food safe plastic and high heat, which I doubt are the cause as it was done in a coopers fermenter in a temp-controlled fridge, at 18 for 2 weeks then 20 for one more. It was then crash chilled and gelatined for about 4 days.

After some more reading I have come up with two possible causes:

1. quote from a thread in 2008,
The Acetone smell is a high indicator of an infection from acetor-bactor.
If this is the case the beer will also have a thin whiteish film across the surface.
I noticed a very thin film on the beer, which caused a few trapped bubbles on the surface, also the krausen was white in some places. Looked as if it was dried out. I can't recall exactly when this occurred, but it may have happened after I gelatined it (was already at ~2C).

2. Possible that I have over pitched? I put this batch straight on the full yeast cake of a previous beer which did not have these smells/flavours.

Attached photo of the fermenter taken a few days ago (3 weeks since pitch) when I noticed white stuff around the krausen and film on top. Shitty photo sorry.
IMAG0247.jpg
 
Does the beer taste like nail polish remover as well, or was it just from the fermentor?

I would say a whole yeast cake is overpitching, but I have never heard that linked to acetone until now. I thought it was linked to infection, but that was probably from reading the same thread on AHB.
 
I tasted it a few days ago, and it had a slight taste but not as over-bearing as the smell coming from that fermenter. I'll go have another taste in a bit after the keg has settled from the force carb.

Not sure if either are factually linked either, but just some possibilities that popped up when looking around. Like I said the main reason for the off-flavour published everywhere is the same, "High temps and non-food grade plastics".
 
Looks infected to me.
Only time i had an assumed aceto infection, looks just like yours, tasted tangy and vinegar like.
Have a look at the infections thread.
 
Thats what I'm fearing. I did make a post the infection photo thread but didn't get much.

Good news is that I tasted the beer, and its drinkable. It's quite noticeable in the after taste but not overbearing, I might just dry hop it or something if it gets too unbearable later on. Hopefully it may fade?
 
Nah, it gets worse.

I had a weizen go wrong on me last year, I noticed the aroma of nail polish from the fermenter after I kegged it, and got worried, and while it was drinkable for a couple of weeks it wasn't what it should have been and I ended up tipping the last half. The remains of the keg smelled much worse than it tasted though.

I retired the fermenter and rained down bleachy vengeance upon the fermentation side of the brewery, and that was the last I saw of it.
 
Has happenned to me once..............taste never goes...............tip it..................infected.
 
Gets worse you say? That sounds a race against time challenge.
 
bbq? Or call Ferg over :)

If the above fail, make batter for chips.
 
Just poured myself a pint after gassing it up ect. I think i lost the challenge already haha. It's unbearable!

So is it def an infection? Could it be the over-pitch of yeast or is that a non-issue?

What to do with infected batch fully carbed..? Clean my beer lines? haha
 
Yes it's an infection. The nail polish/acetone/vinyl type aroma you are getting is generally a wild yeast infection which produces too much ethyl acetate as a by product of fermentation.
 
Definitely an infection, I had the exact same thing on a tea IPA I made a few weeks ago.

Thin white film on top of the beer, heavy paint thinner / smell.

I managed to save it by putting in Polycar VT and crashing it to -1C as soon as I could (I was dry hopping at room temperature with tea leaves when the infection occurred). I racked to the keg after two days of sitting at -1C and left the top 10% or so of the beer, and a didn't drain from anywhere near the yeast/bacteria layer on the bottom of the fermenter.

It's not been 3 weeks since initial infection, and it seems I got rid of the vast majority of bacteria and the "nose" it brings with it. I smell beautiful flowery notes of the Earl Grey, and a nice hint of lemon peel.

I'll let you know if mine gets any worse in the coming weeks.
 
Should I get new fermenters or just nuke these with bleach? I've had 1 for 2 years and 1 a bit less, each has had an infection once, but it has not been continuous.
 
Personally, I like to retire the fermenters after a couple of years or earlier if they have hosted an unwanted bug or some wanted bugs too (my brett fermenter still clearly smells of brett even after a few weeks of bleaching). After two years I reckon I've got my money's worth and they make great grain bins.
 
Yeah got the same problem here...but my problem seems to be from my bottles (lazy adam = lazy cleaning) and its been hit and miss...some smell & taste like beer and some smell and taste like vinegar and nail polish remover :lol:
 
Using your sense of smell around the brewery can be really helpful in avoiding problems,

Though, slightly OT, I've been busy restoring a few old bike parts recently and - if you didn't already know, brown vinegar makes a great rust converter and remover, so I've had various small parts soaking in a container of brown vinegar and I'm happily making dull rusty things shiny again through the magic of chellation.

That is until I check the ferm fridge, take a deep breath and can smell vinegar and start freaking out, until I remember the container of vinegar on the bench behind me that is.
 
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