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-   -   Stuck fermentation... Why? (http://www.homebrewtalk.com/f163/stuck-fermentation-why-367157/)

HollisBT 11-12-2012 04:57 AM

Looking for any reasons, input, suggestions, condolences... My brown ale has been in the fermenters for 2 weeks now, and has only moved 20 gravity points... The recipe is:

Golden promise
Carabrown
Red wheat
C-120
Aromatic

Yeast is wyeast 1450, 1 liter starter for 10 gallons, split into two fermenters

Mashed at 155 for 60 minutes...

Both fermenters started up in <24 hours, krausen coming out of the blow off tube, I thought it was a healthy fermentation, but after 2 weeks its only moved 20 points. Started at a 1.061 now I'm at a 1.041.

I pulled one liter out of one fermenter and pitched a fresh jar of yeast to ensure it is ferment able wort and repitch, but I'm looking for any reasons why or other suggestions to save this beer...

Backporchbrewery 11-12-2012 05:41 AM

Sounds like it could just have been underpitched. For 10gal at 1.061 you'd need a 4-5L starter with only one pack of yeast.

Golddiggie 11-12-2012 05:50 AM

Double check the accuracy of your thermometer. Also, how much of each grain/malt did you use in the recipe?

A 1L starter, even if you used a stirplate, is way too little yeast for that batch size. You needed 431 billion yeast cells for that batch (total). Even if the yeast pack was young, and from the same month, you would have needed a 9.4L starter with intermittent shaking, or 6.2L starter on a stirplate. Going with a two step starter schedule would have knocked those down into lower numbers.

How did you aerate/oxygenate the wort?? Did you add any nutrients to the wort during the boil?

HollisBT 11-12-2012 08:00 AM

Quote:

Originally Posted by Golddiggie
Double check the accuracy of your thermometer. Also, how much of each grain/malt did you use in the recipe?

A 1L starter, even if you used a stirplate, is way too little yeast for that batch size. You needed 431 billion yeast cells for that batch (total). Even if the yeast pack was young, and from the same month, you would have needed a 9.4L starter with intermittent shaking, or 6.2L starter on a stirplate. Going with a two step starter schedule would have knocked those down into lower numbers.

How did you aerate/oxygenate the wort?? Did you add any nutrients to the wort during the boil?

I'll take a look and post up the exact recipe.

My initial thought was under pitched, but would it behave like this of that was the case? It started up quickly and krausened high... Then it just putzed out.

Golddiggie 11-12-2012 03:06 PM

With it kicking off that fast, into full active fermentation, the yeast wasn't the issue (IMO). More likely your thermometer is seriously off and you mashed much higher than you thought. Or your reading the hydrometer incorrectly. Are you using a hydrometer or refractometer? If you're using a refractometer, then you cannot use the raw reading, but need to run it through the software/formula to compensate for the presence of alcohol.

HollisBT 11-12-2012 08:00 PM

Quote:

Originally Posted by Golddiggie
With it kicking off that fast, into full active fermentation, the yeast wasn't the issue (IMO). More likely your thermometer is seriously off and you mashed much higher than you thought. Or your reading the hydrometer incorrectly. Are you using a hydrometer or refractometer? If you're using a refractometer, then you cannot use the raw reading, but need to run it through the software/formula to compensate for the presence of alcohol.

That was my thought too... The thermometer isn't that far off though, I have used it again since with better results. It is possible that I read it wrong though...

I'm using a hydrometer to read the gravity, and have tested it in plain water to be accurate, and measured other batches with it with better accuracy...

The new liter of wort that I pulled off and re-pitched yeast into seems to be starting. I pitched the yeast late sat night, have been shaking intermittently, it hasn't krausend up yet but the yeast are staying well in suspension and it is releasing a decent bit of gas every time I shake it.

With this new starter, do you guys suggest letting it ferment fully and flocking out before pitching it back into the fermenter? Or pitching it at high krausen?

HollisBT 11-12-2012 08:05 PM

Also, the detailed recipe is as follows:


16# golden promise
3# aromatic
3# carabrown
2# red wheat
8oz crystal 120
8oz coffee wheat malt

tre9er 11-12-2012 08:21 PM

Pitch at high krausen. That's a lot of aromatic/cara, FWIW. Test hydrometer in 60* water (your wort samples should be 60* as well). Check thermometer in well-stirred ice-water and in rapidly boiling water.

HollisBT 11-12-2012 08:28 PM

Quote:

Originally Posted by tre9er
Pitch at high krausen. That's a lot of aromatic/cara, FWIW. .

You would still expect more than a 20 point drop from it though...

tre9er 11-12-2012 08:30 PM

What about temp control? How do you do it and what were the actual beer temps during fermentation? If you cooled at any point, it could have encouraged the yeast to fall out. I always recommend a slight warming after initial fermentation has slowed down. That encourages yeast to stay in suspension. A gentle swirl can help, too.


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