Author Topic: Stuck fermentation or is amber malt very unfermentable?  (Read 950 times)

Offline paul

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Stuck fermentation or is amber malt very unfermentable?
« on: December 12, 2013, 10:57:12 PM »
I'm wondering if I have a stuck fermentation or if my beer's just done?

I used  a bunch of amber malt in a biere de garde, 15% by weight.  The rest of the grain bill was pale malt, munich malt, and abbey malt, with no crystal at all.  Mashed at 152 F.  Used Saflager 34/70, pitched two packs of rehydrated yeast for a 1.075 OG, added yeast nutrient, oxygenated as usual, fermented on the warmer side (58 F) and raised temp for the past 6 days to 70 F to try to get it to finish. It's been at 1.026 the for four days.  It really seems like I should have gotten more than 65% attenuation.

I'm wondering if the amber malt is the culprit?  Does it have a low fermentability?

Offline dmtaylor

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #1 on: December 13, 2013, 05:45:18 AM »
It's not the amber malt... unless perhaps you mistakenly used amber caramel malt rather than true amber malt.

Also calibrate your mash thermometer and hydrometer.  In fact this might be the most likely problem of all if you haven't calibrated your equipment recently.

Otherwise, try rousing the yeast, and add some yeast energizer, and wait a couple more weeks.  It might be done fermenting... but don't try to rush things either.
Dave

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Offline Mark G

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #2 on: December 13, 2013, 06:42:13 AM »
Are you measuring your FG with a refractometer by any chance?
Mark Gres

Offline paul

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #3 on: December 13, 2013, 07:28:49 AM »
I used a hydrometer. Didn't use amber caramel (assuming you mean cara amber?), unless the LHBS switched them!  Actually, I tasted the malt and it was definitely not a caramel malt.  The thermometer gets calibrated every batch by noting that it starts at room temperature and registers 203 F in the boiling wort (I'm at 5000 ft).  I've also swirled the carboy several times in the past few days.  Also, I added Wyeast nutrient to the boil, so it seems unlikely it would be nutrient deficient.

I'm wondering about the most proven ways to drop a few more points, assuming the fermentation is really stuck for some reason.  I've read lots of threads over the years about stuck fermentations, and many recommendations are made regarding how drop a few more points.  I haven't seen threads where people report back what worked and what didn't...yeast hulls, pitch dry yeast, pitch an active starter, etc.  Any suggestions what works best?

I have had success with unsticking a fermentation by racking the beer onto a recently flocculated yeast cake, but I don't have one handy at this point.

Offline majorvices

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #4 on: December 13, 2013, 07:33:17 AM »
I used a hydrometer. Didn't use amber caramel (assuming you mean cara amber?), unless the LHBS switched them!  Actually, I tasted the malt and it was definitely not a caramel malt.  The thermometer gets calibrated every batch by noting that it starts at room temperature and registers 203 F in the boiling wort (I'm at 5000 ft).  I've also swirled the carboy several times in the past few days.  Also, I added Wyeast nutrient to the boil, so it seems unlikely it would be nutrient deficient.

I'm wondering about the most proven ways to drop a few more points, assuming the fermentation is really stuck for some reason.  I've read lots of threads over the years about stuck fermentations, and many recommendations are made regarding how drop a few more points.  I haven't seen threads where people report back what worked and what didn't...yeast hulls, pitch dry yeast, pitch an active starter, etc.  Any suggestions what works best?

I have had success with unsticking a fermentation by racking the beer onto a recently flocculated yeast cake, but I don't have one handy at this point.

Sounds like you have done everything right for this style. That said, you haven't mentioned if you calibrated your hydrometer. I've had some off as much as 6 point and I imagine a 1.016-1.018 finish to this beer would not be too high. assuming what you are going for.
Keith Y.
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Offline paul

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #5 on: December 13, 2013, 07:35:09 AM »
If my hydrometer is that far off, then I have a hundred other batches that finished much, much lower than I actually thought!  But I'll check...

Offline paul

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #6 on: December 13, 2013, 07:44:04 AM »
I'll be jiggered.  My tap water is 1.002 at 60 F.  I have to go back and change all of my notes!  Not sure how much mineral content adds, but my water is pretty darn low in minerals.

However, I'm still sitting at 68% attenuation for a yeast that I've always gotten 72-77% from….correction 76-79%!  Those beers both had more crystal and/or were mashed higher than this one.

Offline Wheat_Brewer

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #7 on: December 13, 2013, 07:56:04 AM »
I've had some pretty good success racking the beer from the primary into the secondary with some fresh yeast from the LHBS. I've had mild success racking the beer to a secondary and taking some clean yeast from the primary and giving a gentle stir to "re-activate" the yeast.

If nothing else works I would NOT bottle carbonate for risk of bottle bombs or gushers, but if it tastes alright just RDWHAB.
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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #8 on: December 13, 2013, 08:00:00 AM »
Are you certain that the hydrometer was floating and not resting on the bottom of the cylinder? All of your other procedures sound good, it's the only other thing the catches people up occasionally.
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Offline morticaixavier

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #9 on: December 13, 2013, 09:23:44 AM »
you can perform a fast/forced ferment test to see if you have any more fermentables in there. Just draw off a sample, maybe a pint and pitch a LOT of yeast, a whole packet maybe. if that goes down to where you want it then you can confidently repitch the whole batch with lots of yeast and should see results.
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Offline beersk

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #10 on: December 13, 2013, 09:40:24 AM »
Proven ways to fix a stuck fermentation? Amylase enzyme should do the trick. I have a stout right now that stopped at 1.022 or 1.024, krausen dropped, not happy with that. So I added some amylase, roused the yeast gently with a mix stir and the next morning it had a half inch or so of krausen. I'm hoping it drops it down to 1.016.

I've read others having success with this as well. Sometimes almost too low a final gravity.
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Offline denny

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #11 on: December 13, 2013, 10:00:48 AM »
The abbey malt seems to be a crystal malt.  http://www.northernbrewer.com/shop/weyermann-belgian-style-abbey-malt.html  How much did you use?
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Offline tschmidlin

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #12 on: December 13, 2013, 12:55:00 PM »
Proven ways to fix a stuck fermentation? Amylase enzyme should do the trick. I have a stout right now that stopped at 1.022 or 1.024, krausen dropped, not happy with that. So I added some amylase, roused the yeast gently with a mix stir and the next morning it had a half inch or so of krausen. I'm hoping it drops it down to 1.016.

I've read others having success with this as well. Sometimes almost too low a final gravity.
The problem with amylase is getting it to stop.
Tom Schmidlin

Offline beersk

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #13 on: December 13, 2013, 01:06:53 PM »
Proven ways to fix a stuck fermentation? Amylase enzyme should do the trick. I have a stout right now that stopped at 1.022 or 1.024, krausen dropped, not happy with that. So I added some amylase, roused the yeast gently with a mix stir and the next morning it had a half inch or so of krausen. I'm hoping it drops it down to 1.016.

I've read others having success with this as well. Sometimes almost too low a final gravity.
The problem with amylase is getting it to stop.
Yeah, this is what worries me about the oatmeal stout I used it on the other day.
Watch out for those Cross Dressing Amateurs!

Offline tomsawyer

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Re: Stuck fermentation or is amber malt very unfermentable?
« Reply #14 on: December 13, 2013, 02:12:58 PM »
The abbey malt seems to be a crystal malt.  http://www.northernbrewer.com/shop/weyermann-belgian-style-abbey-malt.html  How much did you use?
Weyermann calls it a base malt and says you can use up to 50%.  I was thinking it sounded like a caramel malt too with the description of honey malt.
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