Can I re-ferment a bottled beer that had stuck fermentation?

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MillStBrews
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Can I re-ferment a bottled beer that had stuck fermentation?

Post by MillStBrews » Thu Mar 02, 2017 9:57 pm

I bottled a Dunkelweizen made from an 'all-malt' kit about 3 months ago. It was a Gozdawa kit made with a Mangrove Jack Bavarian Wheat fermented at 27 deg. C (within range)

I suspected the ferm. had stuck at 1.024 after I had the same hydrometer reading 3 days running. I agitated the yeast but no further movement. I then stirred in the kit yeast which didn't do anything either so I bottled after about 2 weeks as I was worried about it spoiling (having had a few previous batches go sour after being left too long on yeast cake).

After 3 months the beer is conditioning but is super carbed and gushes when opened (it wasn't over primed), it also has a sweet taste, which indicates to me that there is sugar left which could be fermented.

MY QUESTION IS THIS: Can I decant the bottles gently into a FV and add a workhorse yeast to finish the fermentation then re-bottle and prime? I don't want to waste it if it can be saved.

Any advice would be greatly recieved, cheers

MSB

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Kev888
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Re: Can I re-ferment a bottled beer that had stuck fermentat

Post by Kev888 » Fri Mar 03, 2017 4:32 pm

Its not easy to do this, because there are fewer easily-fermented sugars left and quite a bit of alcohol too, so yeast struggle to get going. It also depends on why the fermentation stuck - if the wort is deficient in nutrients or the right kind of sugars (or the temperature too low) for example, the re-pitched yeast may encounter the same problem.

That said, it may be possible to re-start by making a big starter, with plenty of sugars and some nutrient to get the yeast going. There are also re-start yeasts available specifically for this purpose which may help save a brew, though they tend to be fairly unsubtle and won't leave the same flavours or sweetness as the intended yeast.

Given the chances of failure and/or mediocre results you may think it too much effort by this stage. If it happens again, it tends to be easier to deal with things shortly after the fermentation stuck, and whilst still in the fermenter. The gravity being stable does indicate fermentation has almost stopped, but it needs to be at or around the expected Final Gravity too - especially before bottling. Otherwise the fermentation may start again (or continue very slowly) and even cause the bottles to explode..
Kev

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Re: Can I re-ferment a bottled beer that had stuck fermentat

Post by MillStBrews » Fri Mar 03, 2017 8:42 pm

Cheers for that info mate. I will mull it over for a bit but your advice is greatly appreciated.

As a matter of interest I'm drinking a Brewferm Tarwebier now at just over 6 months. Its really nice.

Cheers again mate

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Re: Can I re-ferment a bottled beer that had stuck fermentation?

Post by Wiganbear » Sun Jan 14, 2018 9:35 am

You could decant a couple of bottles into your next beer of a similar style so you don't waste it. I've done this with an ipa I had with the same problem.

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Re: Can I re-ferment a bottled beer that had stuck fermentation?

Post by IPA » Sun Jan 14, 2018 10:15 am

MillStBrews wrote:
Thu Mar 02, 2017 9:57 pm
I bottled a Dunkelweizen made from an 'all-malt' kit about 3 months ago. It was a Gozdawa kit made with a Mangrove Jack Bavarian Wheat fermented at 27 deg. C (within range)

I suspected the ferm. had stuck at 1.024 after I had the same hydrometer reading 3 days running. I agitated the yeast but no further movement. I then stirred in the kit yeast which didn't do anything either so I bottled after about 2 weeks as I was worried about it spoiling (having had a few previous batches go sour after being left too long on yeast cake).

After 3 months the beer is conditioning but is super carbed and gushes when opened (it wasn't over primed), it also has a sweet taste, which indicates to me that there is sugar left which could be fermented.

MY QUESTION IS THIS: Can I decant the bottles gently into a FV and add a workhorse yeast to finish the fermentation then re-bottle and prime? I don't want to waste it if it can be saved.

Any advice would be greatly recieved, cheers

MSB
Gently crack open the crown cork on each bottle so that the excess co2 can escape and leave until no more is escaping. Then spray each bottle neck with Starsan remove the old crown cork and recap with a new one
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Re: Can I re-ferment a bottled beer that had stuck fermentation?

Post by orlando » Sun Jan 14, 2018 11:01 am

Kev's post pretty much covers it. I would advise against trying to referment as you are much more likely to oxygenate the beer in transfer and increase opportunity to infection. Sometimes you have to take it on the chin, learn what you can and shake your head as you pour it down the drain. We've all been there. :roll:
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Re: Can I re-ferment a bottled beer that had stuck fermentation?

Post by MillStBrews » Thu Feb 15, 2018 12:44 pm

Cheers guys for your input.

I am going to try and ferment a small 1ltr with a bit of Coopers kit yeast (that I won't otherwise use) and a bit of yeast nutrient. Mainly out of curiosity.

The question is, do I try and add oxygen to start the yeast off? If I do and it works, I would presumably have to do this with a big starter to add to the batch. However, this would surely give me off flavours in the beer. Catch 22.

Any thoughts?

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Re: Can I re-ferment a bottled beer that had stuck fermentation?

Post by McMullan » Thu Feb 15, 2018 12:57 pm

No need for any O2 with dried yeast.

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Re: Can I re-ferment a bottled beer that had stuck fermentation?

Post by Kev888 » Thu Feb 15, 2018 1:04 pm

Edit: ah beaten to it
I know that i mentioned a big starter, but I should have said 'for liquid yeast'. If you're using dried yeast then I would just go with plenty of that instead.

Aerating/oxygenating is a dilemma at this stage; it is more normal to re-start stuck fermentation in the fermenter, but as I understand it yours has actually been bottled for some time now - I can't say I've direct experience of that scenario. But dried yeast have less requirement for oxygen than liquid yeast so my suspicion is that you will not need to aerate even in these circumstances. If this is just for curiosity then its probably worth a go without, just to see.
Kev

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