Big beer stuck

[rudylyon57]

Have an Imperial Stout that is stuck at 1.050. 5.5 gallons into fermenter, started at 1.120, mashed at 148F, 8 lb Maris Otter, 6 lbs DME, 2 lb Crystal 80 and 4 lbs of dark grains, oats, etc. Fermenting on yeast cake from previous batch which used Muntons Premium Gold. Well oxygenated at start holding 70F.

For reference, the yeast cake came from a similar batch but used grain in place of the DME. It started at 1.112 and finished at 1.030.

Fermentation took two days to get going and moved along at a steady clip for about 4 days where it is now stuck at 1.050. I re-oxygenated and pitched hydrated S04 yesterday but after 24 hours it's looking bleak with no activity. I would like to get to 1030 to 1035.

Any suggestions?

 

[m00ps]

1.120 is a really really high OG. I seriously doubt anything other than a saison yeast is going to be able to cut that down any more.

What are these "4 lbs of dark grain, oats, etc"? Dark specialty malts are not comparable to oats (which are more of an adjunct base malt) in terms of taste or fermentablilty. Depending on how much of that was dark roasted malts you may not get much lower when you take into account the large amount of crystal plus the crystal thats already in DME

 

[SteveHeff]

I'm no yeast expert but I would not reuse yeast that have just completed such hard work on a very heavy wort. I would have made a starter with new and healthy yeast. They may have stalled due to health. Again, I'm not an expert but this is what I find reasonable.

 

[SteveHeff]

Also, depending on what else was fermentable in that "4# of dark grains", this may end up being terminal.

 

[laredo7mm]

Yup, what SteveHeff just said. I don't have any direct experience with it either, but from what I have read it is not good to pitch a high gravity beer on a yeast cake from a previous big beer.

I made the Kate the Great recipe from here on these forums at the beginning of last month. My OG was 1.108 and I had about 5.75 or 6 gallons in the fermenter. I made a 4 liter starter of WY1056, cold crashed it at high krausen, decanted the beer, brought it to room temp, and pitched it into the 68 degree wort. I had active fermentation within 4 hours and it was done in 7 days.

FG was about 1.021 on day seven and the same a week later. With a healthy yeast starter of the appropriate size, an ale yeast can plow through a big beer without any issues.

 

[rudylyon57]

1.120 is a really really high OG. I seriously doubt anything other than a saison yeast is going to be able to cut that down any more.

What are these "4 lbs of dark grain, oats, etc"? Dark specialty malts are not comparable to oats (which are more of an adjunct base malt) in terms of taste or fermentablilty. Depending on how much of that was dark roasted malts you may not get much lower when you take into account the large amount of crystal plus the crystal thats already in DME

The 4 lbs consisted of 1-1/2 chocolate, 1-1/2 flaked oats, 1-1/4 flaked barley, 3/4 black patent, 1/2 roasted barley. I used 6 lb DME to replace 8 lb of maris otter (from original batch). The sluggish nature of fermentation, suggests that the yeast may have been stressed from the previous job.

 

[rudylyon57]

Yup, what SteveHeff just said. I don't have any direct experience with it either, but from what I have read it is not good to pitch a high gravity beer on a yeast cake from a previous big beer.

I made the Kate the Great recipe from here on these forums at the beginning of last month. My OG was 1.108 and I had about 5.75 or 6 gallons in the fermenter. I made a 4 liter starter of WY1056, cold crashed it at high krausen, decanted the beer, brought it to room temp, and pitched it into the 68 degree wort. I had active fermentation within 4 hours and it was done in 7 days.

FG was about 1.021 on day seven and the same a week later. With a healthy yeast starter of the appropriate size, an ale yeast can plow through a big beer without any issues.

Interesting process. Did you re-pitch with your original WY1056? What do you think the advantage of cold crashing and decanting is? Obviously it was successful with your big beer.

 

[Denny]

Your fermentation is not stuck, it's done.

 

[laredo7mm]

Interesting process. Did you re-pitch with your original WY1056? What do you think the advantage of cold crashing and decanting is? Obviously it was successful with your big beer.

I used a smack pack of WY1056 in the starter. I didn't reuse a harvested yeast from a previous beer. To make the starter I used one pound of light DME, 4 liters of water, and a bit of yeast nutrient. Cooled the starter wort to 70 degrees and pitched the smack pack and put on the stir plate.

Cold crashing the starter at high krausen puts the yeast to sleep at peak fermentation as opposed to letting the yeast go dormant after consuming all of the sugars.

Since it was a large starter, I didn't want all the starter beer going into my fermentation vessel with the 6 gallons of wort. I decanted most of the liquid off so what i ended up with was about 1.3 liters of yeast slurry that I ended up pitching into the beer.

 

[laredo7mm]

Your fermentation is not stuck, it's done.

I think it is stuck.

In my RIS that I made it had almost 3 pounds of roasted malts and it finished at 1.021 from an OG of 1.108.

 

[rudylyon57]

Your fermentation is not stuck, it's done.

Denny: Do you say that on the basis of the grist composition? Not sure if you noticed my comment about a similar beer reaching 1.030 and the only thing I did different (except for yeast) was replace 8 lb maris otter with 6 lb DME.

I wish I could dry this thing out a little more.

 

[Denny]

I think it is stuck.

In my RIS that I made it had almost 3 pounds of roasted malts and it finished at 1.021 from an OG of 1.108.

Did it also have DME and 2 lb. of crystal?

 

[Denny]

Denny: Do you say that on the basis of the grist composition? Not sure if you noticed my comment about a similar beer reaching 1.030 and the only thing I did different (except for yeast) was replace 8 lb maris otter with 6 lb DME.

I wish I could dry this thing out a little more.

DME is usually a lot more unfermentable than grain. So, yeah, based on the grist and the starter that was pitched, I think it's done. A fast fermentation test is in order to be sure.

 

[laredo7mm]

Did it also have DME and 2 lb. of crystal?

Here is what I used in my Kate the Great RIS for a six gallon batch:

 

[rudylyon57]

I used a smack pack of WY1056 in the starter. I didn't reuse a harvested yeast from a previous beer. To make the starter I used one pound of light DME, 4 liters of water, and a bit of yeast nutrient. Cooled the starter wort to 70 degrees and pitched the smack pack and put on the stir plate.

Cold crashing the starter at high krausen puts the yeast to sleep at peak fermentation as opposed to letting the yeast go dormant after consuming all of the sugars.

Since it was a large starter, I didn't want all the starter beer going into my fermentation vessel with the 6 gallons of wort. I decanted most of the liquid off so what i ended up with was about 1.3 liters of yeast slurry that I ended up pitching into the beer.

Thanks. I'm learning something now. While it's normally frowned on, do you think re-oxygenating (since I have about .02 or more to drop) is advised in this case?

 

[Denny]

Thanks. I'm learning something now. While it's normally frowned on, do you think re-oxygenating (since I have about .02 or more to drop) is advised in this case?

Absolutely not. If it doesn't ferment, you will have oxidized the beer. Before you can determine the course of action you need to diagnose the problem.

 

[Denny]

Here is what I used in my Kate the Great RIS for a six gallon batch:

You have a lot more unfermentables in the current batch than in this one. Not to mention you really shouldn't reuse yeast from an OG as high as you did. And you OG was much higher this time around.

 

[laredo7mm]

Thanks. I'm learning something now. While it's normally frowned on, do you think re-oxygenating (since I have about .02 or more to drop) is advised in this case?

As Denny said, I wouldn't oxygenate either. I would either look into that fast ferment test that Denny mentioned, or, if it were me, I would make an appropriately sized starter (or a bit bigger since there is no O2) for a 1.050 beer, cold crash it, decant, and then pitch and see if your gravity comes down to the 1.025 to 1.030 area.

 

[rudylyon57]

DME is usually a lot more unfermentable than grain. So, yeah, based on the grist and the starter that was pitched, I think it's done. A fast fermentation test is in order to be sure.

Denny-what is the process for the fast fermentation test you suggest. BTW- thank you for chiming in. I did not realize I had a brewru (Brewing Guru) helping me out!

 

[z-bob]

I rescued one like this last year by adding amylase enzyme and giving it another week or two in the fermenter. I wasn't worried about the high FG, the problem was the beer was too sweet. The amylase dried it out a little; it was still kind of sweet and boozy, but drinkable. I still have 10 bottles aging (I've read the heavy boozy sweet beers age really well) for when the weather turns cold.

 

[Barley_Bob]

This is tough... It's good @z-bob chimed in with a positive experience on amylase. I've only heard negative reviews.

I think I would pitch some brett and get ready for a wait.

 

[Denny]

Denny-what is the process for the fast fermentation test you suggest. BTW- thank you for chiming in. I did not realize I had a brewru (Brewing Guru) helping me out!

Pull some of the wort and put it in a container...any container. Add a buttload of yeast to it...any yeast, even bread yeast is fine. Leave it at room temp for a couple days then check the gravity again. The idea is to give it the most "fermentable" conditions possible and see what happens.

If it ferments more like that, then you can try to "rescue" the batch. If it doesn't. it's done. I would caution you against things like amylase or Beano because they're so uncontrollable.

 

[helibrewer]

Next time you plan a big beer you can do the fast ferment up front, breweries often do this in their labs. Take a liter of your wort and do as Denny describes above, basically overpitch it and keep it 70-72F, even stir plate if you wish. It will finish in 24-36 hours and will give you an indication of the absolute lowest you MIGHT expect for an FG. It may not get their, but at least it tells you the theoretical low value.

 

[pdxal]

The points about grist and poor yeast management are good.
Nobody has mentioned the fact that you are only 6 days into fermentation, though. You should give it more time, too, and see if the gravity comes down further. Same gravity for 3 days straight, assuming conditions like temp are correct, and it is finished.
I wouldn't even bother checking gravity on a beer this big for a couple of weeks, and would probably let it sit on the yeast for 3-4 weeks to clean up regardless.

 

[Denny]

The points about grist and poor yeast management are good.
Nobody has mentioned the fact that you are only 6 days into fermentation, though. You should give it more time, too, and see if the gravity comes down further. Same gravity for 3 days straight, assuming conditions like temp are correct, and it is finished.
I wouldn't even bother checking gravity on a beer this big for a couple of weeks, and would probably let it sit on the yeast for 3-4 weeks to clean up regardless.

Excellent point!

 

[rudylyon57]

Thanks to all for your inputs. I started a fermentation test yesterday so we'll know soon what the potential of this wort is. My bet is with Denny and it is done without enzyme modification. Enzyme modification may be the basis for a second test.

 

[rudylyon57]

Pull some of the wort and put it in a container...any container. Add a buttload of yeast to it...any yeast, even bread yeast is fine. Leave it at room temp for a couple days then check the gravity again. The idea is to give it the most "fermentable" conditions possible and see what happens.

If it ferments more like that, then you can try to "rescue" the batch. If it doesn't. it's done. I would caution you against things like amylase or Beano because they're so uncontrollable.

Update: I took Denny's advice and performed a fermentation test with S04 (stir plate, O2 and 75F). Nothing-nada-zilch for SG reduction which suggests the remaining sugars are not fermentable as-is. In parallel with that test, I added amalayse enzyme to another 1.5L sample and in three days I was down to 1.045 with visible signs of activity shortly after starting the test.

Since this beer is too sweet to drink and would otherwise be tossed, I decided to dose the batch with amalayse enzyme and seems to be responding like the test. Here is where I need advice. I would like to see this drop to 1.03 ish. My present plan is to rack and cold crash when there. I assume that keeping it in a keg at 38-40F while aging will cease further yeast activity? IT WILL NEVER BE BOTTLED OR ALLOWED TO WARM. Sound reasonable?

 

[Denny]

I wouldn't count on being able to stop fermentation by cooling it. AFAIK, the only things that stop amylase are running out of sugar, or denaturing it with heat. In the future, if you have a situation like this, consider brewing a very bitter batch and blending them.

 

[Mer-man]

What about diluting with boiled water? Make a brown ale out of it. Try that with a portion.