Help with possibly stuck fermentation

OK, so I have a sweet stout going I think may be stuck. I had a problem with a stopped fermentation with this yeast on a bigger stout I made earlier this year.

Here is the recipe:

• 4oz Dark Choc Malt
• 4oz Roasted barley
• 8oz 120L Caramalt
• 1.5 lbs Amber LME
• 3.3 Lbs Pilsner LMS
• 3.3 Lbs Dark LME
• 8oz maltodextrine
• 8oz lactose
• .5oz Magnum early add
• .5oz Cluster late add
• 5oz hard cooked and very drained bacon. Added late boil.
• Danstar Nottingham yeast - rehydrated

Temps have been a steady 66F. At day 3 airlock showed regular activity. By day 8 this had ceased. It is day 11 now. I took a sample. 1.028, and the krausen has fallen.

That gives me an apparent attenuation of about 55%. while the spec sheet for Nottingham does not give a percentage, it states high attenuation. I would expect that to mean 70% or better. I do have a bit of unfermentabales in here, but not 15% of my bill. I will sample again tomorrow (then I am gone for 2 days). It may still be dropping slowly, and it got some small agitation when I sampled today so we will see, but I am leery of this yeast because it stuck on me before.

Besides relaxing and having a beer (I will), what do you guys and gals think? I do need to get this into secondary in about 2 weeks to make room for another beer for an event.

What was your target FG? You have lactose, maltodextrine, and the dark malts so I would expect a high gravity finish. The lactose alone will add about 4 points and I would guess the maltodextrine adds about that so I think you are fine.

With the dark grains, the dark LME and the lactose, it is a beer that will not finish low. I am guessing it may be close to going as low as it is going to go. So if it does not change in the next couple of days. It is done.

Beer smith said 1.019, and I figured it calculated well. At any rate, I am soaking oak chips in whiskey and sanitizing my secondary. In about half an hour I will rack it over and sample again. I will let you know where it landed.

Thanks

BradTheGeek said:

Beer smith said 1.019, and I figured it calculated well. At any rate, I am soaking oak chips in whiskey and sanitizing my secondary. In about half an hour I will rack it over and sample again. I will let you know where it landed.

Thanks

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No, Beersmith is fairly useless at predicting FG. It just guestimates a % of the attenuation.

If it's done, it's done. With maltodextrine, dark malts, dark LME, and lactose, I would expect a very high FG.

Well, it is racked and chips added. FG 1.026-1.027
I am going to nudge temps up a touch, but I doubt it will go much further. It will condition in the secondary for at least 2 weeks, with perhaps a dry hopping of a small amount of bacon near the end.

The sample I pulled tasted amazing, so if the jack barrel chips + jack do it any justice this will be a great beer. Had coffee notes with just a hint of bacon/meatiness.

If anyone wants a sample, there is a great event coming up in Charlottesville VA, Homebrew for Hunger. Date not announced yet, but should be end of October. Come get some great beers and support a noble cause!

Hey guys - I just wanted to share a similar problem I'm currently having making a porter and see if the answers are similar to Brad's.

I brewed a porter recently which had a target ABV of 4.8% - decided to add another 1.4kg of Maris otter base malt to bump the ABV up (also because my previous mash/sparges haven't been all that efficient) so I didn't want to risk less/weak beer.

So, original gravity hit 1.072, target gravity is 1.017, but measured today (after 7 days at 21c, it's at 1.027. So 6%ABV, but still way under what it should be. Measured with a hydrometer.

It was a 5gal (UK) (6US Gal) batch and I used a single vial of wyeast WLP005 British ale yeast, well aerated wort I think but found after pitching that a little was still left in the vial.

So I have two questions - one - do you guys think this will continue to ferment? It's pretty quiet right now.

Two (more importantly I think) - when I bottle this - if I was going to bottle to 2.2vols co2, should I adjust this to take into account stuck fermentation so they don't over carb and produce off flavours in the bottle?

Look forward to hearing what people have to say about this and Brad's as this has happened to me before too!

Cheers

Two concerns: You wildly underpitched and you don't seem sure whether or not you aerated.

A "proper" pitch for this batch would be 346 billion cells (4 billion per point of O.G. per 5 gal US batch): 4 * 72 * 6/5 = 346 billion. One vial of yeast contains between 70 and 140 billion cells. Assuming average viability (105 billion cells), minus 5 billion cells for the little bit you said left in the vial (wild-ass guess), let's say you pitched about 100 billion cells. That means you underpitched by 71%. You pitched less than a third of the "optimal" number of yeast cells.

A batch that big would also require good aeration to give the yeast a good running start. Anything over 1.060 would actually benefit more from oxygenation than mere aeration. So if you neglected to thoroughly aerate the wort, then that's another big factor that's going to impact attenuation (not to mention off-flavours from stressed yeast).

All that said, to really diagnose a stuck fermentation, we'd need to know the recipe, mash temperature, and specific yeast strain. In my opinion, true "stuck" fermentations are actually extremely rare, and the vast majority of the time, it's simply a "done" fermentation, i.e. all fermentable sugars have been consumed. I think you're (unfortunately) probably as low as your gravity is going to go, which means you're likely safe to bottle, but the beer is going to end up sweeter than intended.

Yooper said:

No, Beersmith is fairly useless at predicting FG.

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Oh so true, yet not nearly as bad as some batch kit instructions. Some of those expected FGs are laughably low.

Kombat thanks so much for that - I'm still pretty new to this (6th batch) so think I need to look into making yeast starters. Presume making a big enough starter would be the easiest next step, followed by buying oxygen to use pre-pitch if it's still coming out low?

Also, I re-measured after a further 3 days and it's hit 1.024, so 6.4% now. Still 0.9% under so pretty significant, but slightly less sweet which is good.

Cheers guys

ChrisMoss said:

Kombat thanks so much for that - I'm still pretty new to this (6th batch) so think I need to look into making yeast starters. Presume making a big enough starter would be the easiest next step, followed by buying oxygen to use pre-pitch if it's still coming out low?

Also, I re-measured after a further 3 days and it's hit 1.024, so 6.4% now. Still 0.9% under so pretty significant, but slightly less sweet which is good.

Cheers guys

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it's a porter so a little conditioning won't hurt it anyways. one thing kombat forgot to mention was, "leave it the floc alone." every time you dip in there to test the OG means another chance you're introducing infectious creatures. there's really no need for checking gravity on a beer like that at day 7. at day 10, you're likely at FG, but who knows, if you warm it up a bit, and let it sit for at least another week, it might happen to drop another couple points, but don't hold your breath on that.

i highly suggest on your next brews to really look up and try to follow a proven recipe or bjcp style guidelines, especially if it's a style you've not brewed before. look up specifics on OG and FG, mash temps, mash rest times, yeast pitch rates, fermentation temps, fermentation length, etc. before you brew it.

i've been brewing for a little over a year now, and i've tried doing some experiments of my own. about half of which have honestly not been good beers at all. still drinkable, but not good. the other half were pretty average. so for the past few months, i've just started brewing proven recipes only, for the most part from people on here. now i'm brewing really good beer, while still trying to refine my palette, and be able to distinguish the difference between different malts, hops, yeast characteristics, etc. i figure after some time of doing this, that i will have not only a knowledge base of what all those flavors should be, but an experience base as well. which will allow me to make very informed recipe decisions in the future.