Stalled Fermentation - any tips?

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monty1
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Stalled Fermentation - any tips?

Post by monty1 »

I've brewed a Scottish ale with honey, OG was 1.04 and it's been fermenting for 7 days now with a current gravity of 1.02, instead of the target 1.01. It took 2 days before there was visible signs of fermentation in the airlock, it fermented vigorously for a few days and has a healthy looking krausen on top.

I used this Whitelabs Edinburgh yeast http://www.themaltmiller.co.uk/index.ph ... ductId=174
I pitched it to a litre or so of wort at 22 degrees to give it a start then added to the rest at 22 degrees after 20 minutes or so.
Mash temperature was 67 degrees and was mostly spot on, so I think the remaining sugar should be fermentable, though some could be unfermentable sugars from the yeast.

ABV is a little low at around 3%, but I'm more concerned that if there is fermentable sugars left in there, i'll have a case of bottle bombs.

It was a little chilly in the fermentation area, the bubbling seemed to start up properly when I warmed it up.

Any advice on what to do now? I'll check gravity daily to monitor for change, but should i just try and warm it up, stir in the krausen and get some extra oxygen in, pitch more yeast?

Thanks,

Iain
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Taz Ales
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Re: Stalled Fermentation - any tips?

Post by Taz Ales »

If the yeast has flocculated to a pack at the bottom of the fermenter you can try getting it going again by lifting the vessel onto a tennis ball and rolling it round in circles for a minute to stir up the yeast. Take the airlock off and put a bung in while doing this.
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steve crawshaw
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Re: Stalled Fermentation - any tips?

Post by steve crawshaw »

monty1 wrote: I used this Whitelabs Edinburgh yeast http://www.themaltmiller.co.uk/index.ph ... ductId=174
I pitched it to a litre or so of wort at 22 degrees to give it a start then added to the rest at 22 degrees after 20 minutes or so.


Any advice on what to do now? I'll check gravity daily to monitor for change, but should i just try and warm it up, stir in the krausen and get some extra oxygen in, pitch more yeast?
If i understand you correctly you made a starter, but only let it ferment for 20 minutes? That will not have achieved anything. You need to make a starter 12 - 18 hours prior to pitching and ideally pitch when the starter is at high kraesen. Control your fermentation temps with an aquarium heater in a water batch with your FV in the bath. This is important if your ambient temps are varying significantly.

If you've only been fermenting for 7 days, leave it for another 7 before checking gravity. I would leave for 2 weeks from pitch as a matter of course before checking gravity. every time you check gravity you risk infection. Resist the urge to continually inspect your beer while it is fermenting.

To fix this current situation, which I have seen before with WLP028, and if no improvement after total primary ferment of 2 weeks, pitch a fresh starter - as outlined above, at high krausen. You can use any yeast. That will finish it off.
cheers
steve
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monty1
Posts: 80
Joined: Tue Sep 24, 2013 3:47 pm
Location: BS3

Re: Stalled Fermentation - any tips?

Post by monty1 »

If i understand you correctly you made a starter, but only let it ferment for 20 minutes? That will not have achieved anything
I did, directions suggested pitching straight to the wort, I thought a 20 minute start in a little wort followed by mixing into wort would have been better. Might try the starter next time.
If you've only been fermenting for 7 days, leave it for another 7 before checking gravity. I would leave for 2 weeks from pitch as a matter of course before checking gravity. every time you check gravity you risk infection. Resist the urge to continually inspect your beer while it is fermenting
.

Will leave it a week until i next check, of course you are right, every check could infect it - wasn't thinking straight!

Will follow the advice, if there's no shift in a week.

Cheers all
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