Fermentation stops at 1.050...now what?

As the title says my gravity is at 1.050 after repitching yeast in my big stout and I have no activity.

OG 1.142
Mash temp 155
Mash ph 4.9 is what I calculated, not sure what happened there

Grain bill for mash
29lbs Maris Otter
1.5lbs oats
1.5lbs rye
1.5lbs special b

Grain bill for cold steep...36 hours in cold water then strained
1 lb each
Crystal 120
Roasted Barley
British Chocolate

Other
.5lbs molasses

Pitched a 4l starter of Dry English Ale WLP007 with 60 seconds of pure O2 fermenting at 65f. After a week I was down to 1.050. That makes sense since the yeast tolerance is less than the 12% I hit. I had a 2l starter of super high gravity WLP099 that I then pitched. 4 days now and no activity, took samples.

What happened? Is the 2l starter of 099 really not enough to get this fermenting? I did raise the temp to 70f, I did rock the bucket back and forth a few times...have not tried to stir yet. Beersmith shows that this should get down to 1.034? I did a similar ABV stout last year but with all extract and got it down to 1.021.

Any suggestions?

So, no movement at all on the SG with the 099 on board? Woof!

Calibrated your mash thermometer lately?

Cheers!

is it at all possible it is done... 1.142 is a monster stout and you mashed that pretty high 155. that combined with the oats rye and another 4lbs of specialty grains. my guess is that you mashed too high Especially if 099 isn't doing anything. you could add some dextrose to try and dry it out or pitch some brett that will go to work on the longer chained sugars that the regular yeast cant eat

My mash thermometer is the blichmann on the pot but I also use a thermapen. The issue with the thermapen is I normally get different reading since it takes it from the top of the pot. The thermapen actually had a slightly lower reading.

The Brett sounds like a preferred method to try first. Is there a certain type of Brett I should use. Do you recommend making a starter and how large? Are there going to be any negative effects with using Brett?


The second method is Dextrose you mentioned. My goal was 15% so if I add 2.5lbs of dextrose my OG would jump to 1.165 and 15.1% ABV if it all fermented out. How does that sound?

depends on what you want... the Brett is defiantly going to change the character of your beer and might make it a little funky which might be good or bad (depending on if you like that or not) I would throw some white labs WLP644 Brettanomyces bruxellensis Trois if you go brett. It is a bit more mild on the brett front. Also make a starter and step it up a few times. brett from white labs is a reduced cell count so I would do a 1l starter for 3-4 days then a 2l starter for 3-4 days and possibly another 2l starter just to get your counts up. also in that environment 12% abv you will need to give the brett some time to work as these are less than optimal conditions.

if you are going do option 2 i would add maybe 1/2 lb of dextrose to start off with and see if the gravity moves at all... if it ticks down a few points than you can add some more and try and get it where you want it. the reasoning is if lack of simple sugars is not your issue and the yeast doesn't kick back up you are just making the situation worse by adding more sugar (dextrose)

Are you sure it's stuck, or not just finished? A beer can be stuck usually if the temp suddenly drops to the yeasts dormancy/flocculation point. So swirling warming does indeed work. Or rarely the yeast tires out, and swirling it back into suspension will help bring it down a few more points.

But what most new brewers think is a stuck fermentation is usually a matter of the yeast eating all the fermentables and finishing high, like what we call the 1.020 or 1.030 curse. If you mashed too high and got a lot of unfermentables, or in the case of extract, a lot of unfermentables/caramelization. Nothing you can do short of maybe adding an alpha amalaze to "break" the unfermentable sugars down will work.

Swirling won't, warming it up won't, heck even adding more yeast won't. A beer can be done high, and nothing's really wrong.

For example I have a barleywine that is FINISHED at 1.040. The og was 1.170 and it has a lot of caramel malts and extremely dark (50 year old) honey in it. That dark translates into unfermentable sugars. It's been multiply yeasted, and has been sitting in a tertiary for close to two years. Despite the numbers it is finished, NOT STUCK, there's just nothing left for the yeast to eat.

It's a big beer....it really doesn't matter necessarily if the FG is high, but whether it is done or stuck

the more i think about it the more i would not add the dextrose.... if you wanted to get a couple points lower it might work but not worth the risk in my opinion. I would make a big brett starter, pitch and check it in a month.. that is assuming you want it drier.... How does it taste now? it may be fine as is

Wondering if you aren't using a refractometer to check your FG? WLP099 can take big beers down way too dry, so I would expect some reduction in gravity after re-pitching.

Revvy...I think it's stuck but I could be wrong. I say stuck because Beersmith shows my estimated fg to be 1.034...that's quite a bit off from 1.050. If Beersmith is wrong on their logic then I guess it could be done fermenting in which case I probably mashed too high. I just assumed from previous experience that the 099 would take a few points off after the 007 finished and it didn't at all.

My next step is to sample it, I know I should have done this a while ago but I have just enough beer to fill my 5g bourbon barrel and didn't want to loose any volume. I assumed it would be too sweet but maybe it won't be. I'll report on it tomorrow.

agm163...this is a imperial stout, not sure how the Brett would go with this style, probably not appropriate?

Daksin....not using a refractometer...traditional hydrometer

I'd bet you're done. You got 65% attenuation, which is feasible. Beersmith simply assumes a certain % attenuation without knowing anything about your mash temps, amount of unfermentables, etc. You are well "outside the box" here, so you may not get the typical attenuation.

I recently made a 1.104 stout with 1056 that finished at 1.040, which is 62% attenuation. Fortunately I was heavy on the hops, so balance is fine.

I'm starting to get more and more confident that the fermentation is done. Again a taste test should help me decide. Thanks.

quick experiment.... change your mash temp in beersmith does your FG estimate change at all??? I think you mashed too high and it is as fermented as it is going to be with conventional yeast.... but this is merely gut instinct. 099 is a beast of a yeast if there were anything in there it could eat it would

I agree, probably done. However, just a thought... That is a beast of a beer, and you are likely to age it for some time regardless of your packaging method. I would recommend leaving it in primary for at least 6 weeks or so, and then transfer to a C02 purged secondary and let it sit... for a long time. It may just be SLOW dropping like some Belgian strong ales I have made. If you are bottling, I would NOT recommend bottling for at least a few months. If you are kegging, use the keg (if you have a spare) as the secondary, purge, transfer, and then forget about it for about a year

I did a taste test last night. It wasn't crazy sweet. It did have a lot of body to it which is understandable. The good thing is I had a decent amount of hops in it which have no problem coming through in the beer, particularly the finish. This beer is good as is but could thinning it out make it better?

I have an opportunity to get 1litre of a house strain yeast from a local brewery that makes some big beers. There yeast normally attenuates in the mid 90% but they think it would probably get my bear in the low 80%. Theoretically if it hit 80% attenuation it would bring my beer down to 1.028 only if there really are fermentables left in there. If that amount of beast yeast can't do the job then I know the fermentation is just finished and I mashed too high.

I'm having trouble deciding what to do...I might have a friend come taste the beer for a second opinion. My gut tells me that it needs to dry out more.

ajm163...changing the mash temp in beersmith does change the estimated fg. At 155 mash in step temp fg is 1.030, at 146 1.028. The odd thing is that at 160 fg is 1.028...I would have thought it would increase the fg above the 155 temp. Not sure if their logic is accurate or not.

SpeedYellow said:

I'd bet you're done. You got 65% attenuation, which is feasible. Beersmith simply assumes a certain % attenuation without knowing anything about your mash temps, amount of unfermentables, etc. You are well "outside the box" here, so you may not get the typical attenuation.

I recently made a 1.104 stout with 1056 that finished at 1.040, which is 62% attenuation. Fortunately I was heavy on the hops, so balance is fine.

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What he said

Beersmith simply assumes a certain % attenuation without knowing anything about your mash temps, amount of unfermentables, etc

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when I change my mash temp it changes the fg....I just tested it. Beersmith does seem to account for mash temps in their fg logic.

An alternative which I didn't see mentioned above, is to make a lower gravity stout and blend them after it's done to cut the residual sugars.

An even more radical approach would be if you have the fermentor space, brew a medium gravity stout, get into primary fermentation, and blend it with your big stout once primary fermentation is rocking away. If the yeast did stall while leaving fermentables behind, this method would add a substantial amount of actively fermenting yeast to your beer, while at the same time cutting the unfermentable percent. I see this requiring two more fermentors beyond the one the big stout is in.

strongarm said:

when I change my mash temp it changes the fg....I just tested it. Beersmith does seem to account for mash temps in their fg logic.

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Ok, they must have added that to the current version, since my older version doesn't do that. Does it also try to account for less-fermentable stuff like crystal and oats? Regardless, it's just a guesstimate, and a beer like this can easily fall outside of Wyeast's standard attenuation ranges.

poley said:

An alternative which I didn't see mentioned above, is to make a lower gravity stout and blend them after it's done to cut the residual sugars.

An even more radical approach would be if you have the fermentor space, brew a medium gravity stout, get into primary fermentation, and blend it with your big stout once primary fermentation is rocking away. If the yeast did stall while leaving fermentables behind, this method would add a substantial amount of actively fermenting yeast to your beer, while at the same time cutting the unfermentable percent. I see this requiring two more fermentors beyond the one the big stout is in.

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+1 This is a great idea. I used the second method mentioned above to dry out and reduce spicing of a winter warmer a few years ago (you'd be amazed what 1 oz of ground mulling spice will do!!!). Worked out great.

Just checked my FG 1.036. Looks like there was a serious lag time on that second pitch. This matches my 099 pitch I did last year on a similar beer....dropped it an additional 15 points. 20 brews in and I still am too impatient:/