Stuck Fermentation

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Second Home
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Stuck Fermentation

Post by Second Home »

Alright guys. Quick question. 10 gallon batch of Irish Stout, pitched 2 vials of Liquid Irish Ale yeast. OG was right on target at 1.046. Target was 1.011. Bubbling only went for a couple days then stopped. Did a reading after about a week and was at 1.023! Not bubbling anymore. Is it stuck? What can I do at this point? I was thinking about making a starter and pitching that. Any feedback would be great.
Thanks!
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CurtisG
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Re: Stuck Fermentation

Post by CurtisG »

Bubbling isn't the best way to tell if fermentation is still going. I've had leaky fermentation buckets that don't bubble at all.

At 10 gallons, 2 vials is still underpitching. which should explain the slow fermentation.

How long has it been fermenting? I would take another gravity sample and see if it is still at 1.023. If it is the same for a few days in a row then you know it is stuck/done.
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Second Home
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Re: Stuck Fermentation

Post by Second Home »

Ok cool. First question, If it is stuck/done, can anything be done to push it along furthur?
2nd question, is 2 vials still under pitching if you do a starter? We didn't on this one, I was just curious...
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Justin H
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Re: Stuck Fermentation

Post by Justin H »

We may need a little more info, but first check the lid to make sure you seal is air tight if your fermenting in a bucket. I have heard people assume their fermentation had stopped because there is no airlock activity and the only problem was a loose lid. If it's not the lid, take another reading in a few days and see if there is any change.

Are you fermenting at ambient temperatures or are you able to cool and/or warm the vessel your fermenting in? If the temp dropped there's a good chance that you can get it going again by just moving it to a warmer more temp stable location. If it doesn't pick up on its own go ahead and pitch a healthy active starter, and keep it warm.
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Re: Stuck Fermentation

Post by JonW »

A starter with 2 vials can yield a proper pitch rate as long as it was propagated enough. You should use a pitch rate calculator to get you in the neighborhood.

How was your mash temp? That could be affecting what you're seeing with a bunch of unfermentable sugars. Could also just be the yeast. Hard to tell at this point.

Some things to try:
- Rouse the yeast by swirling the fermenter
- Raise the wort temperature to around 70
- Wait a few days to see if there is progress.

If all else fails, you could go the amylase enzyme route. Read up on this first to ensure you're using it correctly. Here's one reference for it: http://hbd.org/brewery/library/enzymes595.html
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CurtisG
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Re: Stuck Fermentation

Post by CurtisG »

I would suggest trying to warm the batch up and rouse the yeast a bit to get it to finish out.

Another odd question for you. Are you using a refractometer or hydrometer? If you are using a refractometer make sure you are adjusting for alcohol content. http://www.northernbrewer.com/learn/res ... alculator/
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Justin H
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Re: Stuck Fermentation

Post by Justin H »

Second Home wrote:Ok cool. First question, If it is stuck/done, can anything be done to push it along furthur?
2nd question, is 2 vials still under pitching if you do a starter? We didn't on this one, I was just curious...
It would depend on the size of the starter. Mr Malty would have you use 3 packs is a 2.68 l starter if the packs are fresh. If you are only going to use 2 vials I would make a 4 l (or two 2 l) starter.
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brahn
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Re: Stuck Fermentation

Post by brahn »

Like the others said, take another sample. Only way to know if it's done is if you've taken successive readings with no change.

If it hasn't dropped, I would do like Curtis and Jon have suggested: warm it up a little and try to rouse the yeast. If that doesn't work, I'd just enjoy it for what it is. Or dump it.

I think trying to "fix" a beer that doesn't meet you expectations with things like Amylase just takes your focus away from the next beer and isn't going to get your beer where you really want it to be.
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