# Acetone Off Flavour



## Acasta (10/9/12)

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,


beersom said:


> 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.


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## felten (10/9/12)

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.


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## Acasta (10/9/12)

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".


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## [email protected] (10/9/12)

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.


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## Acasta (10/9/12)

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?


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## white.grant (10/9/12)

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.


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## Rowy (10/9/12)

Has happenned to me once..............taste never goes...............tip it..................infected.


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## Acasta (10/9/12)

Gets worse you say? That sounds a race against time challenge.


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## pk.sax (10/9/12)

bbq? Or call Ferg over 

If the above fail, make batter for chips.


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## white.grant (10/9/12)

Acasta said:


> Gets worse you say? That sounds a race against time challenge.



Good luck


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## Acasta (10/9/12)

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


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## white.grant (11/9/12)

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.


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## unco_tomato (11/9/12)

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.


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## Acasta (11/9/12)

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.


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## white.grant (11/9/12)

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.


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## tricache (11/9/12)

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:


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## white.grant (11/9/12)

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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## fcmcg (11/9/12)

practicalfool said:


> bbq? Or call Ferg over
> 
> If the above fail, make batter for chips.


Why would i get invited over ???


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## manticle (11/9/12)

Because you wear a lot of nail polish?


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## jyo (11/9/12)

manticle said:


> Because you wear a lot of nail polish?



Don't all Collingwood supporters?


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