Stuck Ferment / Under Attenuation Issue?

[Siscokid85]

Hi All,

First proper post and I am cap-in-hand after some advice please. I have brewed a GEB Dingemans Belgian Dubbel Kit and struggling with fermentation. (Very impressed with my first few kits / custom kit orders from GEB by the way).

Brewed it 31.07.22. I looked likely to miss the predicted OG by a bit, so I extended the boil for 40 mins to bring that up to 1.063. (having fished the hop tea bags out after an hour). This was as per BF predictions but +4points over the GEB instructions. I still don't have my equipment profile fully dialled in for my new set up as yet, but I got to the BF predictions with the extra boil time.

I set it fermenting with the supplied Lallemand Abbaye Belgian yeast, dry pitched it and after a couple of days it started chugging nicely. BF / GEB instructions states an FG of 1.007 / 1.006, it has now levelled off and it has stopped at 1.015 for the last 3 days. I have increased the temp and given it a gentle stir to see if that helps, but nothing yet. Is this too close to the predicted FG to be described as a stuck fermentation, or is it more just not fully attenuated? Does anyone have any advice to try and get it a bit further along or should I just be happy with it and accept it might be a little sweeter / weaker than intended? All advice appreciated as never had a fermentation miss the FG by more than a point or 2 - usually I end up with over attenuation issues!

Summary of stats:

Predicted on BF - OG = 1.063 / FG = 1.007 / Alc 7.4%
GEB instructions - OG = 1.059 / FG = 1.006 / Alc 6.9%
Currently / actual - OG =1.063 / FG = 1.015 / Alc 6.3%

Also I noticed on BF it tells me a "Post boil gravity" of 1.060 and a "total gravity" of 1.063 - anyone know the difference? The kit has 500g of belgian candi sugar in it, but thought this would be included in the post boil figure as added with 10 minutes to go??

Anyway a lot of questions there, but appreciate any advice on any of the points. Thanks in advance.

 

[Sadfield]

How many packs of yeast?

Lallemands app suggests more than one, for 25L of 1.063 wort.

If GEB have been shoddy and only supplied one, I'd say it may have stalled from not enough yeast and a slightly more dextinous wort from the extra boiling.

 

[Siscokid85]

How many packs of yeast?

Lallemands app suggests more than one, for 25L of 1.063 wort.

If GEB have been shoddy and only supplied one, I'd say it may have stalled from not enough yeast and a slightly more dextinous wort from the extra boiling.

Ahh only 1 pack of yeast, must admit i didnt read the label or research it.

Is there any benefit from buying a second pack and repitching now, or do you think it is too late?

 

[Sadfield]

The first post of this is worth looking at.

https://www.thehomebrewforum.co.uk/...s-for-dealing-with-stuck-fermentations.74910/
You could, or something neutral live Notty, SO4, US05... will suffice.

 

[Siscokid85]

The first post of this is worth looking at.

https://www.thehomebrewforum.co.uk/...s-for-dealing-with-stuck-fermentations.74910/
You could, or something neutral live Notty, SO4, US05... will suffice.

Ahh thanks for the help, I have a pack of Nottingham in stock, so will add that and see what happens.

 

[Siscokid85]

Hi,

Me again! I took the plunge and ordered another pack of the Lallemand belgian abbaye yeast, rehydrated it and pitched it, another few days and nothing, I guess the alcohol levels are too high for it to establish. I dont have propagation kit to be able to grow anything on and create a proper starter which might have stood more chance.

I have been in touch with GEB to give them feedback and they have been very helpful in offering ideas and said they will review the kit. I am inclined to package and just go with a slightly sweeter beer that is 0.5% less than intended, rather than potentially ruining it by trying to get the last few points fermented out. I had always intended on bottling this, I was going to batch prime and bottle. However do you think bottling at 1015 this is risky for over carbonation or bottle bombs??

I could keg, but I dont relish the idea of getting through 19l of 6.5% beer, the keg will be hanging about for ages at the rate i drink something of that strength.

The other option which GEB suggested was pitch a Kviek and lift the temp a bit?

Thanks in advance for any help.

 

[dmtaylor]

Adding more yeast to a "stalled" beer never helps IMO. It's just finished. Yeast is a living organism and will do what it wants. In this case, this strain is done. And the alcohol and lack of fermentable sugars will indeed prevent any new yeast from taking it further. Just leave it and enjoy it.

 

[Agentgonzo]

I've experienced a few brews where it doesn't attenuate as per the recipe. I've had the same experience as @dmtaylor in that fresh yeast won't do anything (if the previous yeast can't ferment the sugars, then fresh yeast won't). On the plus side, unfermentable sugars don't taste anywhere near as sweet as fermentable sugars (under 30% as sweet as maltose according to some sources I recall reading, but don't have the link to hand) so it doesn't affect the taste of the beer as much as you may initially think.

 

[phildo79]

Adding more yeast to a "stalled" beer never helps IMO. It's just finished. Yeast is a living organism and will do what it wants. In this case, this strain is done. And the alcohol and lack of fermentable sugars will indeed prevent any new yeast from taking it further. Just leave it and enjoy it.

Agreed. I have given up on trying to get stalled fermentations going again. I have tried multiple suggestions but none of them ever worked. Add more yeast, rouse the yeast cake, add enzymes etc. All failed. My problem now seems to be that my beers ferment beyond the target FG.

 

[Sadfield]

Can't say I've experience of it. Trying on the off chance doesn't cost much, though, both financially and in end product. There's enough anecdotal evidence it can work. There's different reasons for fermentation to stall, this one being purely down to underpitching and needing more yeast.


The extra fresh yeast should help with bottle conditioning, if that's the way it's going to be packaged.

Good to hear GEB are reviewing the recipe.

 

[Siscokid85]

Hi

Thanks for the replies and advice. Never had this problem before, normally i have over attenuation by 2-3 points!

I may just go with bottling it. @Sadfield would you be worried about the high FG of 1015 and bottle bombs? or does the fact the remaining complex sugars wont ferment in the FV mean they stand little chance in the bottle? Would you just prime as normal with brewing sugar? I was aiming for 3.0-3.5 vols in line with the style guide. does that sound ok in this situation?

 

[dmtaylor]

would you be worried about the high FG of 1015 and bottle bombs? or does the fact the remaining complex sugars wont ferment in the FV mean they stand little chance in the bottle? Would you just prime as normal with brewing sugar? I was aiming for 3.0-3.5 vols in line with the style guide. does that sound ok in this situation?

These are good questions. Some Belgian yeasts do lag for a bit then pick up a second fermentation later. However yours has been sitting still for the better part of 17 days now, so I think it is probably safe to bottle. If you want extra insurance, just leave it alone for one more week to see if it takes off a second time. I figure odds of this happening are about 30%, based on my experience with Belgians. Honestly not sure what I would do in your situation. Flip a coin?!

I would never prime that much for bottling. I have bottled >160 batches since 1999. Too much priming is a real problem. I'd rather be conservative on priming and have a standard carbonated batch than 50 gushers or bombs. So aim instead for about 2.5 volumes CO2. I don't care what other people recommend; it just isn't worth the risk.

 

[Sadfield]

Hi

Thanks for the replies and advice. Never had this problem before, normally i have over attenuation by 2-3 points!

I may just go with bottling it. @Sadfield would you be worried about the high FG of 1015 and bottle bombs? or does the fact the remaining complex sugars wont ferment in the FV mean they stand little chance in the bottle? Would you just prime as normal with brewing sugar? I was aiming for 3.0-3.5 vols in line with the style guide. does that sound ok in this situation?

I'd give it at least another week if not two.

Regardless of the high FG, it's pretty un-Belgian to rush from fermentation to packaging that quickly.

3.5 vols is fine if the FG is correct, but gives no wiggle room if you're not 100% confident it's done.

 

[Siscokid85]

cool thanks @dmtaylor and @Sadfield I will maybe give it another gentle stir then leave it for another week. think im done with throwing yeast in it now though!

I will do a manual reading tonight to confirm, but no reason to think the tilt is lying. I try and avoid bottling, but figured this would be more authentic for the style and anyway who wants a keg of strong belgian dubbel (dangerous).

I have invested so much time and (now) 2 packets of yeast into it I think I take on board @dmtaylors thoughts in terms of risk v benefit, and actually having something to drink for my efforts. if some of the residual sugar gets used up I might be lucky and get nearer 3 volumes, but if not i will just give it a slightly more vigorous pour!

If I had a second FV and ferm fridge maybe i would be in less of a hurry but thanks for being my brewing conscience and slowing me down!

 

[Sadfield]

If you've a spare corny, it would be a perfect maturation vessel/conditioning tank for a few weeks. Then just transfer out to a bottling bucket when ready. That's almost what I do, except I've a Beer Gun, so I just add sugar (and a little champagne yeast) to the corny prior to bottling straight from it.

That'll free up your fv and fridge.

Probably a bit too adventurous, but interesting. To achieve 4. 25 vols of Co2, Duvel force carb c2 vols then prime and bottle condition the rest of the way.

 

[Siscokid85]

If you've a spare corny, it would be a perfect maturation vessel/conditioning tank for a few weeks. Then just transfer out to a bottling bucket when ready. That's almost what I do, except I've a Beer Gun, so I just add sugar (and a little champagne yeast) to the corny prior to bottling straight from it.

That'll free up your fv and fridge.

Probably a bit too adventurous, but interesting. To achieve 4. 25 vols of Co2, Duvel force carb c2 vols then prime and bottle condition the rest of the way.

thats a great idea, it is a 25l batch though, could use 2 spare cornys and just purge the headspace.

although realistically with family commitments, it is probably going to be September before I get a chance to brew again I think. might just leave be

 

[Siscokid85]

Hi, Quick update, I have done a manual hydrometer reading tonight and it has dropped 1 point since Friday (when I checked and pitched the 2nd packet of yeast) to 1014. I use a large scale hydrometer with individual point markings so I am fairly positive I am not getting mixed up or have misread. there is no noticeable activity on the surface or in the air lock (no bubbles in the starsan solution).

I presume it is possible to have fermentation going very very slowly and be dropping SG with no obvious signs of fermentation? Anyway unless I have got mixed up or am seeing things (possible but unlikely) I think it is definitely weight to the argument from @Sadfield and @dmtaylor to leave it another week or two.

Let me know of any thoughts.

Again appreciate the advice.

 

[phildo79]

I'm far too impatient to wait an extra week or two for the sake of 0.5%. can't imagine it will make too much difference to the end product.

 

[Sadfield]

Looks like there may be some hope yet. Abbaye has a high alcohol tolerance and high attenuation.

 

[Agentgonzo]

I presume it is possible to have fermentation going very very slowly and be dropping SG with no obvious signs of fermentation?

Yes, that's very possible, Fermentation tails off, rather than just abruptly stopping.