Stuck fermentation? help

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Stuck fermentation? help

Postby andrewmaixner » Tue Nov 25, 2014 10:58 am

Got no input on a bigger forum, so cross posting here too:

Style: Dry Stout (13A)
Bitterness: 36.4 IBUs Boil Time: 60 min
Est OG: 1.047 (11.6° P) Mash Profile: Single Infusion, Medium Body
Est FG: 1.012 SG (3.2° P) Fermentation: Ale, Single Stage

10.00 g Gypsum (Calcium Sulfate) (Mash 60 min) Misc 2
1.00 tbsp PH 5.2 Stabilizer (Mash 60 min) Misc 3
5 lbs Pale Malt (2 Row) UK (2.5 SRM) Grain 4
2 lbs Barley, Flaked (1.7 SRM) Grain 5
1 lbs Black Barley (Stout) (500.0 SRM) Grain 6
2 lbs Pale Malt, Maris Otter (3.0 SRM) Grain 7
2.0 oz Goldings, East Kent [5.0%] - Boil 60 min Hops 8

1 pkgs Irish Ale Yeast (White Labs #WLP004) Yeast 9

Notes:
OG 11/8/14 1.052 5.7 gallons wort. 5.5 into fermenter.
mash ended up being 90 minutes in the 152-153F range, then 10 min at 165F.
Pitched the yeast vial at 65F, as I did not yet have equipment for a starter -- I now do have that equipment.

It appears to have stalled at 1.023 and has stayed there for 12 days now.
Rising the temperature to 70F for a week, and agitation, did not restart the fermentation.
1)What are the options to get the gravity down?
2) Should I harvest some yeast from the bottom and build up a starter to re-pitch?
3) Or would it be better/easier to make a starter with some US-05 I have sitting around and pitch that at high krausen?
4) is it possible that my thermometer was off, mash was too hot, and I now have a Sweet Stout instead of a Dry?
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Re: Stuck fermentation? help

Postby Matt F » Tue Nov 25, 2014 2:56 pm

I have very little experience with the Irish Ale strain. Not sure how it likes to behave. I would try the new pitch of US-05. Still not working, then throw in some Champagne yeast.

As for thermometer being off, it is highly possible. I use to take multiple readings of the mash with a floating thermometer in addition to my dial thermometer mounted on my kettle. Temps were often all over the place. I use to brew with 1.1 qts/lbs. of grain. I now use 1.5qts or more. That has helped make a more uniform mash temp. Problem with thermometer is it still only measures one small part of the mash. Basically as you brew, you get comfortable with what your thermometer tells you. You learn what works for you and repeat. I find with my current constantly recirculation mash method, I have very uniform mash temps and the kettle thermometer is fairly accurate.

Basically, thermometers are like friends. You don't have to trust them, you just have to know and/or understand them.
Matt Franklin
Slappy Brewing North

On Tap:
Saison
Matt Damon in my Mouth
Tree House Julius Clone

Fermenting:
Belgian Dubbel/Sour
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Re: Stuck fermentation? help

Postby whitedj » Fri Nov 28, 2014 12:54 pm

Test the thermometer. Boil some water and it should read about 209 to 212. If your much off of that then there is likely an issue. Also note how long after immersion in the water it takes to reach equilibrium.

When I re pitch yeast I usually just hydrate dry and throw it in. Yeast flavor is not likely affected by an additional pitch.
In my barley wine I usually pitch Nottingham to drop it a couple additional points.
Also I've noticed some strains get lazy and drop out if temp is too cool then they are slowing down.
The guy who submitted a barley wine in the Furious competition...
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Re: Stuck fermentation? help

Postby andrewmaixner » Tue Feb 17, 2015 2:31 pm

whitedj wrote:Test the thermometer. Boil some water and it should read about 209 to 212. If your much off of that then there is likely an issue. Also note how long after immersion in the water it takes to reach equilibrium.

Following up, I do believe that my thermometer was 5 degrees off. I fixed the adjustment and relegated that thermometer to places where only 'close enough' is needed, and I now have a digital instant-read Themowand.

In any case, I kegged the stout a while ago, it was dry, it was a hit, now I have to make more.
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