Contaminated beer EVERY time!

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FirebladeAdam

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I'm being driven slightly mad by this. This is the fourth brew that smells like the delightful scent of farts! A few days into fermentation it starts to smell. It doesn't change the taste of the beer, but it certainly makes the beer smell. It fades to almost nothing after a month or more in bottle, but I have sanitised everything, bleached, cleaned, scrubbed... It's only happened during the cold weather. Never had anything like it before. Could it be something to do with my brew fridge? I can smell it when I open the fridge or before! Anyone any idea what is going on?
I've thrown one batch away, let one batch sit in bottle for weeks (it's good beer, but not as good as usual), dry hopped one batch which seemed to help the smell (I'm bottling that in a couple of days) and the current beer is currently honking away like a cocking camembert.
Any help or advice greatly appreciated.
 

Paul7189

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My fermentation fridge smells terrible when you open the door but that’s just the smell that comes from fermentation. Never get it carried over to the beer. Are you using plastic fermenters? You can get scratches that harbour bacteria and sanitiser won’t work it’s way into the scratch and kill it off. Try a new fermenter if it’s plastic and see if that changes anything.
 

Paul7189

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Also are you reusing your yeast or going for fresh stuff? Is it all grain or extract brewing?
 

MickDundee

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What yeast(s) are you using? Some are more prone to producing sulphur during fermentation than others, and if it doesn’t affect the taste of the beer and fades to nothing after a month in the bottle I would assume that’s the cause of your problem. I definitely wouldn’t be throwing beer away if it clears up after a month!

How long are you leaving in the FV before bottling?
 
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I've had a couple of brews that smell of eggs part way through fermentation but seem to clear up by the end of two weeks and the resulting beer does not have any off smells / tastes.

Are you expecting it not to smell after a few days? I think it's perfectly normal during fermentation.
 

FirebladeAdam

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I'm an all grain brewer. I do reuse yeasts, but all of these brews apart from one have been fresh yeasts. I've used Wyeast 1215, Nottingham, and US05. I know the smell can be strong during ferm, I'm well used to it, but this is different. The plastic bucket thing.... I have scrubbed it out with bleach and rinsed and then sanitised and then having experienced the same outcome, done the same thing with a second plastic bucket. It's almost not possible for a bacteria to make it past what I've done! On the plus side, I've learned that however good your sanitation it can be better. I've even scrubbed the hot liquor tun and the mash tun.
 

FirebladeAdam

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Sorry there was one I didn't answer, about how long it's in the FV. 2 weeks. I do the whole 2+2+2 thing. Only now it's 2+2+2+4. I don't measure the FG with beers I make often, I just have the full 2 weeks, it's never not worked! That's not to say it won't go wrong one day.
 

FirebladeAdam

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I've had a couple of brews that smell of eggs part way through fermentation but seem to clear up by the end of two weeks and the resulting beer does not have any off smells / tastes.

Are you expecting it not to smell after a few days? I think it's perfectly normal during fermentation.
Im expecting it to smell a bit for through primary and then not smell at all when I bottle. It's currently sulphuric and farty when I open the fermenter after 2 weeks
 

FirebladeAdam

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Do you control your fermentation temperature?
Yes, the ferm fridge is set to 19C. It has a heat mat for heat, and that's wired to the controller, as is the mains for the fridge. It's a pretty standard setup I've never had an issue with it before.
 
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A cheesy smell might be isovaleric acid which comes from oxidised alpha acids (old hops, hops that have been open for a long time, or hops not stored cold). Have you used a particular bag of hops in this last four brews? If it is isovaleric acid it does fade over time but fresh hops will of course immediately fix any new brews.
 

FirebladeAdam

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A cheesy smell might be isovaleric acid which comes from oxidised alpha acids (old hops, hops that have been open for a long time, or hops not stored cold). Have you used a particular bag of hops in this last four brews? If it is isovaleric acid it does fade over time but fresh hops will of course immediately fix any new brews.
Good idea, might be, I freeze them but I do leave them open. They're all pellets and some are BBC, I often part use a packet and put them back in the freezer. But annoyingly nothing I haven't done before! Lots of different hop types too
 

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