HELP: Fermentation stalled at 56% attenuation!

[seanppp]

I have been brewing BIAB for ten years and have only recently started fly sparging. I have been getting terrible efficiencies (in the low 60s) but I think that's because I sparge too fast. Anyway, last week I brewed an imperial stout with a 60% mash efficiency. The wort didn't taste as sweet as I'm used to in my IPAs, but I wasn't sure if that was the roasted malts covering up the sweetness. In any case, I was worried that I didn't convert all the starches (although it's hard to figure out why that would be, I mashed at 156F for 80 minutes). Well, I ended up with a 1.089 after adding some sugar (2.5% of the total fermentables) to the boil. I oxygenated the wort, dosed the yeast according to Mr Malty, and pitched at 64F and let the beer rise to 68F. Here are the gravities per day:

1.089 Brew day
(????) after 1 day
1.060 after 2 days
1.044 after 3 days.
1.038 after 4 days.
1.038 after 5 days.
1.038 after 6 days.
1.038 after 7 days.

It would appear I have a stuck fermentation! Do you think I didn't get complete conversion and the yeast are done fermenting what they can? What do you suggest I do now?

Thanks!

 

[jdauria]

How much yeast did you pitch? A 1.089 beer needs more that one vial or pack.

What kind of yeast did you pitch? Was it a high flocculation style? If so, the yeast may have just dropped out, gently stir the carboy to get the yeast back in suspension.

Lastly, give the beer time. If you pitched the proper amount of yeast then it is probably OK, you have a big beer there and it may need another week to fully ferment.

Personally, I don't recommend taking reading every day. Unless you are purging with CO2, every time you open the carboy to take a reading, you are letting oxygen in to the beer. I just let my beers go the X number if days it's suppose to and then take a reading last two days to see if it is done.

 

[Fat_Bastard]

stuck fermentations suck
try racking the beer on to a fresh yeast cake, preferably one that hasn't worked to hard.I have gone as far as boiling up a 5 gallon extract "starter". ferment it out like a normal batch of beer with temp control then crash,decant it off and rack my stuck batch on top of it.

 

[seanppp]

I pitched the right amount of yeast and oxygenated. I am wondering if I didn't get a full mash conversion... That is a good idea to pitch on a new yeast cake, though. Maybe I'll have to do that.

 

[seanppp]

Oh, and it's the Safale US-05 strain. Should be attenuative.

 

[ArcaneXor]

If it's incomplete conversion during mash: Add amylase enzyme, or Ultra Ferm
If it's stalled due to poor yeast health, pitch a vial of WLP 099.

These work 95% of the time.

 

[seanppp]

You can add amalyse enzyme during fermentation?!

 

[aryoung1980]

How often do you mash at 156F?

That seems high to me and without doing any actual math, I would expect a beer mashed at that temperature to have a fair amount of unfermentables left in the finished product.


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[Hello]

How often do you mash at 156F?

That seems high to me and without doing any actual math, I would expect a beer mashed at that temperature to have a fair amount of unfermentables left in the finished product.


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This is where the newbie in me comes in because Beer Smith actually tells me for a full bodied beer, to mash at 156F but my OG on the recipe is 1.124.

OP: US-05 shouldn't stop at 56% but if there is nothing left to eat then there is nothing left to eat. You can actually take a cup of the beer, put it in a flask or growler, pitch an entire package of yeast (try US05 or champagne yeast) and see if that ferments. If it does then you know you have some fermentables and somehow the yeast was stressed. If not, then it's done. I did that with my milk stout. It was just done at 1.024 even though I expected it to drop to 1.018 at least. I used champagne yeast, that's a beast that is tolerant of high alcohol and goes dry. It is worth a shot.

I would also do that test but leave it for a few days. I may not be as seasoned as most around here but disturbing your wort every day from the date you brew is unnecessary and mostly counter productive to the process, if you ask me.

 

[Fat_Bastard]

You can add amalyse enzyme during fermentation?!

ya but I wouldn't,you can't control how how it works.I have tried it and it drove my gravity in to the basement.there may be some magic number of how much to use to prevent it from over attenuating but I have not found it.
My best results have always come from using ALOT of fresh yeast from another beer.

 

[ArcaneXor]

You can add amalyse enzyme during fermentation?!

Sure - it just works more slowly. I have used it several times. I prefer the liquid solutions that Brewcraft distributes - they are called AMG 300L (beta amylase) and Termamyl (alpha amylase). Any homebrew shop that has a brewcraft account should be able to order these for you. They are also great to use if you ever screw up your mash temperature.

There is also amylase enzyme powder available from several wholesalers, but most are not labeled, i.e. you aren't quite sure if you get alpha, beta, a mix, or something else entirely.

Ultraferm is much more aggressive and should only be used if all else fails.

 

[RM-MN]

Are you using a hydrometer or a refractometer to measure the gravity of the beer?