Stuck fermentation

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Neddy

Stuck fermentation

Post by Neddy » Sat Feb 27, 2016 11:08 am

I'm a noob to all grain brewing and seem to have a stuck fermentation. I brewed on 13 Feb and my OG was spot on at 1045. I pitched 10g of dried Mangrove Jack yeast at about 20 deg C and did not aerate the wort.

Initial fermentation seemed slow but steady. After 10 days the gravity was 1020 (target FG is 1009) and very little activity through the airlock. Today, another 4 days on and we're still at 1020.

Any ideas please?

BrannigansLove
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Re: Stuck fermentation

Post by BrannigansLove » Sat Feb 27, 2016 11:50 am

What temperature did you mash at? I had a similar experience on my first AG brew. My mash temp control was a little wayward, and I had mash temps up to 72c at times. Only fermented down to about 1018. I bottled and drunk it anyway (was a nice beer). It was a good experience in understanding how you can control body and ABV with mash temps.

Neddy

Re: Stuck fermentation

Post by Neddy » Sat Feb 27, 2016 12:25 pm

The mash temp was 66c with a 10 min mash out @ 75c.

Padalac

Re: Stuck fermentation

Post by Padalac » Sat Feb 27, 2016 12:32 pm

maybe it got cold?

Neddy

Re: Stuck fermentation

Post by Neddy » Sat Feb 27, 2016 1:07 pm

The FV stands quite close to the aga so the wort seems a steady 20c.

hazelbrew

Re: Stuck fermentation

Post by hazelbrew » Sat Feb 27, 2016 1:46 pm

Neddy wrote:I'm a noob to all grain brewing and seem to have a stuck fermentation. I brewed on 13 Feb and my OG was spot on at 1045. I pitched 10g of dried Mangrove Jack yeast at about 20 deg C and did not aerate the wort.

Initial fermentation seemed slow but steady. After 10 days the gravity was 1020 (target FG is 1009) and very little activity through the airlock. Today, another 4 days on and we're still at 1020.

Any ideas please?

which mangrove jack yeast? over on the US boards there are lots of reports of low attentuation for some of the MJ yeasts.

Neddy

Re: Stuck fermentation

Post by Neddy » Sat Feb 27, 2016 3:25 pm

It was the Empire Ale M15.

BrannigansLove
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Re: Stuck fermentation

Post by BrannigansLove » Sat Feb 27, 2016 6:13 pm

What are you using to measure your gravity? Refractometer or hydrometer?

Padalac

Re: Stuck fermentation

Post by Padalac » Sat Feb 27, 2016 8:17 pm

yea, i've had pretty bad experiences with MJ yeasts

Neddy

Re: Stuck fermentation

Post by Neddy » Sun Feb 28, 2016 11:22 am

BrannigansLove wrote:
> What are you using to measure your gravity? Refractometer or hydrometer?

I'm using a hydrometer.

Any suggestions as to where to go from here? Do I try and kickstart the process or go with what I've got and leave it there?

scotsloon
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Re: Stuck fermentation

Post by scotsloon » Sun Feb 28, 2016 11:40 am

You can do a couple of things. You can give it a stir, but be careful, stir gently so that you are not adding air to the brew. This will get the yeast suspended in the brew and may help it to start fermenting again. Secondly you can increase the temp a little, maybe up to 22 or 23 *C but don't go higher.
Good luck with it.

BrannigansLove
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Re: Stuck fermentation

Post by BrannigansLove » Sun Feb 28, 2016 3:56 pm

Also you could pitch some more yeast, something clean and with a higher attentuation, US05 or Nottingham perhaps.

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