Stout hasn't reached final gravity

Larse · Oct 19, 2024

Caramel Ox said:
Yes keg prime and enjoy then! And stop worrying about the numbers.

Then you can decide if you like it - it’s a bit of a kitchen sink recipe, more like porter than stout to my eyes.

Will do and thanks everyone for all the help.

I'm not really a stout drinker, I made this for my two sons who are. I tasted it when it had got down to 1.018 and was cross checking the SG. At that stage it had a distinct chocolate flavour and nice bitterness. Probably a tad sweet to my taste. Hence the desire to get the FG down a bit more.

It was a first foray into stout/porter. Will look around for other recipes when this is finished. But I'd say that could be a while since I've made a keg and a half of it. :beer1:

Erik The Anglophile · Oct 19, 2024

Since no-one else said it I'm gonna do it.
1.052-1.014 for a stout/porter isn't something I consider out of the ordinary.
I don't think you'd find many commercial (English) stouts or porters attenuated much over 75%

Sadfield · Oct 19, 2024

Erik The Anglophile said:
Since no-one else said it I'm gonna do it.
1.052-1.014 for a stout/porter isn't something I consider out of the ordinary.
I don't think you'd find many commercial (English) stouts or porters attenuated much over 75%

That's because the OP liqoured back to 1.045.

Erik The Anglophile · Oct 19, 2024

Ah, must have missed that part.
Then it's a bit on the sweeter side...

foxy · Oct 20, 2024

Larse said:
Will do and thanks everyone for all the help.

I'm not really a stout drinker, I made this for my two sons who are. I tasted it when it had got down to 1.018 and was cross checking the SG. At that stage it had a distinct chocolate flavour and nice bitterness. Probably a tad sweet to my taste. Hence the desire to get the FG down a bit more.

It was a first foray into stout/porter. Will look around for other recipes when this is finished. But I'd say that could be a while since I've made a keg and a half of it.

Look on this forum or any other forum for that matter there are plenty of threads about a stuck stout ferment. Some brewers fail to grasp that there are a lot of unfermentable sugars in a stout, while they contribute to an OG reading, when it comes to the FG the non-fermentable sugar's presence gives the impression that the fermentation has stalled.
I would suggest 'if' you brew another try a hochkurz mash schedule which will extract more fermentable sugar and either steep, hot or cold the none fermentable or just put them in for a 20-minute mash out.

Sadfield · Oct 20, 2024

The dark portion of this recipe is only c12% of the grist, and most of that is fermentable, although the sugars from those grains are more complex than they would be from pale malt. In my experience most recipe calculators predict this difference very well. Without those dark grains the predicted FG would likely have been around 1.009. And that is where the issue is here, the predicted FG wasn't reached. Its a fermenting issue, not a mashing one. Yeast consume sugars in order of complexity, monosaccharides first, dextrins last. The yeast didn't reach the end of fermentation in the best shape to process those sugars. If you habitually start mashing for high fermentability and then have a good fermentation, you'll end up with dry stouts.

Brew_DD2 · Oct 20, 2024

Sadfield said:
Its a fermenting issue, not a mashing one.

Sadfield said:
If you habitually start mashing for high fermentability and then have a good fermentation, you'll end up with dry stouts.

I mean, it could be a mashing issue if more unfermentables were extracted than intended.

Larse · Oct 20, 2024

Brew_DD2 said:
I mean, it could be a mashing issue if more unfermentables were extracted than intended.

I'm leaning towards this. It could still be related to under pitching the yeast, but generally doesn't this manifest as slow initial fermentation activity, which wasn't the case here?

The unexplained rise in SG a couple of days after adding the AA also has me scratching my head.

Sadfield · Oct 20, 2024

Larse said:
Mash temp was 66° which I pretty much nailed for the hour.

If your process matched that of what the recipe calculator, I'm inclined to think not.

My understanding is, that when yeast creates a daughter cell, it splits the vacuole between each sell. The vacuole is where necessary amino acids and phospates are stored. So, with a low pitch rate you end up with yeast that requires more splits, you end up with yeast doesn't have enough of what it needs to complete fermentation.

foxy said:
Look on this forum or any other forum for that matter there are plenty of threads about a stuck stout ferment.

@Brew_DD2 It was also a reply to this observation. Where anecdotally many of the posts are kit brews, where the mashing was done commercially, and consistently. With kits working for some and not for others.

Larse · Oct 20, 2024

Sadfield said:
If you process matched that of what the recipe calculator, I'm inclined to think not.

Sorry, don't get what you're saying here.

Sadfield · Oct 20, 2024

Larse said:
Sorry, don't get what you're saying here.

If the recipe calculator estimated fermentability based on 66°C and you matched that exactly in practice, you should see the same fermentability.

Larse · Oct 20, 2024

Sadfield said:
If the recipe calculator estimated fermentability based on 66°C and you matched that exactly in practice, you should see the same fermentability.

It was a kit. No recipe calculator. Or at least not that I was given. There wasn't even a notional efficiency rate. I probably could have put it through a calculator, might still do, but I wasn't arsed at the time.

starseeker · Oct 20, 2024

I very likely would not be arsed about a three point difference in the fg to be fair ,:)

Larse · Oct 20, 2024

starseeker said:
I very likely would not be arsed about a three point difference in the fg to be fair ,:)

<pedant> 4 point </pedant>

Joking aside, It may not be significant (although it's 3.9% instead of 4.5% ABV), finding out why something went awry, even if not very significant is surely the best way to proceed?

starseeker · Oct 20, 2024

You are quite right ,
I also see that it has only being in the fermenter roughly a week ,a lot of us leave it in for two weeks or so as it is surprising how long some yeast take to chew through the last percentage points ,

Jahfish · Oct 20, 2024

Brew_DD2 said:
I mean, it could be a mashing issue if more unfermentables were extracted than intended.

And 66 could do this?

peebee · Oct 20, 2024

Erik The Anglophile said:
Since no-one else said it I'm gonna do it.
1.052-1.014 for a stout/porter isn't something I consider out of the ordinary.
I don't think you'd find many commercial (English) stouts or porters attenuated much over 75%

Thank goodness; someone has injected a bit of sense! S-04 while being passed off as "a bit boring" doesn't ferment the guts out of beer like, say, US-01.

Erik The Anglophile said:
Ah, must have missed that part.
Then it's a bit on the sweeter side...

Ah ... don't spoil it!

Left over dextrin from fermentation isn't particularly sweet. Can add a good bit of mouthfeel though (daft thing to say ... bits of broken glass in the bottom of your pint adds lots of mouthfeel too).

I'm horrified if my beers drop as low as 1.014 (I'm horrified if I find broken glass in me pint too).

Larse · Oct 20, 2024

starseeker said:
You are quite right ,
I also see that it has only being in the fermenter roughly a week ,a lot of us leave it in for two weeks or so as it is surprising how long some yeast take to chew through the last percentage points ,

Cheers. But it's in two weeks yesterday. And pretty much flatlined after a few days. It's cold crashing now, then will be kegged and primed and kept for a week or so at room temp before going in the kegerator.

I'll let you all know how it turns out. Cheers for all the information and advice. I've learned a lot. athumb..

Brew_DD2 · Oct 20, 2024

Jahfish said:
And 66 could do this?

Nah, not in this case. Just think it pays to keep an open mind on whether mash vs. fermentation causes a higher than expected FG.

In this case, it's likely the grist/fermentation.

Larse · Oct 23, 2024

As a sort of an update on this, I brewed Dave Line's London Pride recipe on Sunday. Pitched S-04 into the wort in a brewing bin (this is a more 'traditional' fermentation - primary in bin, secondary in carboy and then keg). This morning it had reached 1.012 (trigger level for secondary).

The wort volume was around 19L, so I reckon the problem with the stout was under-pitching.

Stout hasn't reached final gravity

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