S-04 under-attenuating for dark beers

[Sandimas]

I've just bottled my 3rd dark beer in succession and got a higher FG than expected: not stuck, just a bit high. The OGs weren't particularly high 1046-1050 and from my notes the yeast attenuation with Safale S-04 has been 68%, 62% and 67%. In comparison, golden/amber beers with the same yeast have come out mugh higher attentuation, 77%, 77% and 78%. The Fermentis spec sheet says 74-82%, so all the dark beers are below the lower limit. All beers were mashed and fermented at the same temps.

In comparison, my dark beers made with other yeasts (Gervin, MJ) come out much better: 74%, 77% etc attenutaion.

Anyone else noticed this?

 

[matt76]

I've only used S-04 twice, both times in a couple of porters brewed in short succession (never used it in anything else so don't know about paler beers).

Both were mashed at 68/69degC, both started at 1.039/1.041 and both got 70% attention coming in just south of 4% ABV.

 

[Pennine]

I haven't noticed it but it's very interesting seeing data points like this. Seems like there are less fermentables in your dark beers. What's a typical recipe look like?

 

[Sandimas]

Typically for the Porters 77% pale malt, 10% crystal, 10% brown malt and 3% black malt.

The thing is, I was originally going to post this under the heading "why are my dark beers under-attenuating", thinking like you it was due to the less fermentable grains. However, when I looked back at my records, this only happened with S-04 yeast, other yeasts managed to eat through the wort better and achieve attenuation in the 70s and even the 80s. So it's not the grains, it's the yeast. I've since done a search and some people on the US forums have noticed the same with S-04.

The resultant beers are fine, just a bit weaker ABV-wise.

 

[foxy]

I've just bottled my 3rd dark beer in succession and got a higher FG than expected: not stuck, just a bit high. The OGs weren't particularly high 1046-1050 and from my notes the yeast attenuation with Safale S-04 has been 68%, 62% and 67%. In comparison, golden/amber beers with the same yeast have come out mugh higher attentuation, 77%, 77% and 78%. The Fermentis spec sheet says 74-82%, so all the dark beers are below the lower limit. All beers were mashed and fermented at the same temps.

In comparison, my dark beers made with other yeasts (Gervin, MJ) come out much better: 74%, 77% etc attenutaion.

Anyone else noticed this?

Are you checking your pH? Darker beers are more acidic, and when pH gets to around 4.2 the yeast will stop working.

 

[Obadiah Boondoggle]

What I have noticed is that Safale S-04 seems to create a fast and furious fermentation where the temperatures become too high i.e. 28C - so had to cool them down

 

[foxy]

What I have noticed is that Safale S-04 seems to create a fast and furious fermentation where the temperatures become too high i.e. 28C - so had to cool them down

All yeast will go hard at it if the temperature is too high, best to start off low 16-17 C to compensate for the exothermic activity.

 

[DCBC]

All my very dark beers seem to finish a bit high and I tend to use S04 for nearly all of them. It can lead to problems with bottle conditioning because those last couple of gravity points do end up getting chewed through eventually, leading to some rather fizzy beers! I don't know if it's the yeast or the malt bill. I do adjust for pH in Brunwater so it shouldn't be that.

 

[foxy]

All my very dark beers seem to finish a bit high and I tend to use S04 for nearly all of them. It can lead to problems with bottle conditioning because those last couple of gravity points do end up getting chewed through eventually, leading to some rather fizzy beers! I don't know if it's the yeast or the malt bill. I do adjust for pH in Brunwater so it shouldn't be that.

In darellm's case it sounds like he is not adding enough carbonate to achieve a lower FG, in your case if your yeast is struggling but eventually getting there then I would be looking at the pitch rate of your yeast.

 

[DCBC]

In darellm's case it sounds like he is not adding enough carbonate to achieve a lower FG, in your case if your yeast is struggling but eventually getting there then I would be looking at the pitch rate of your yeast.

Cheers, good advice. I always give non-kveik beers a fortnight but there is something in the combo of 04 and dark malts which takes a little longer for me. I'd certainly rather give the beer another week in primary and have well-carbonated beer.

 

[Sandimas]

I did used to check my pH but stopped when I ran out oh pH papers, I'll look into it next time.

Doesn't change the fact that it only appears to be S-04 struggling to get down, other yeasts are fine. I've subsequently found quite a bit of discussion on this on various forums.

 

[foxy]

I did used to check my pH but stopped when I ran out oh pH papers, I'll look into it next time.

Doesn't change the fact that it only appears to be S-04 struggling to get down, other yeasts are fine. I've subsequently found quite a bit of discussion on this on various forums.

I would be looking for a decent pH meter, or keep your salt additions simple for stouts and porters by milling the base malt and the none fermentables separately and adding the none fermentables at mash out or just as a late addition.

The yeast which you choose as a brewer is down to style and your own preference. There are 3 types of yeasts apparent attenuation, low, medium and high.
You mentioned the Gervin yeast I presume ale which is Danstar Nottingham yeast re badged
that is the high range, the Fermentis SO4 is a medium so what you are comparing is apples and oranges.
If you want a dry finish then go for the high AA, but it wouldn't be suitable for something like a mild ale you would have to pick a lower attenuating yeast.

 

[Obadiah Boondoggle]

All yeast will go hard at it if the temperature is too high, best to start off low 16-17 C to compensate for the exothermic activity.

Thanks - but my point is that the temperature is too high

The fermenting bucket is in my garage where the ambient temperature is around the level you suggest

The action of the yeast has increased the temperature to 28C

Also interestingly - this is 15L of Robinsons Old Tom

OG when yeast pitched on 2/10/20 - 1070

SG today (5/10/20) 1012 - my target was 1016

Fermentation so fast worries me but it tastes good

 

[Pennine]

Typically for the Porters 77% pale malt, 10% crystal, 10% brown malt and 3% black malt.

The thing is, I was originally going to post this under the heading "why are my dark beers under-attenuating", thinking like you it was due to the less fermentable grains. However, when I looked back at my records, this only happened with S-04 yeast, other yeasts managed to eat through the wort better and achieve attenuation in the 70s and even the 80s. So it's not the grains, it's the yeast. I've since done a search and some people on the US forums have noticed the same with S-04.

The resultant beers are fine, just a bit weaker ABV-wise.

It sounds like the affect of the grains on the yeast then if other yeast chew through it fine. Is there something about the sugar released in roasted grains that could affect s04? Sorry no help here although I am very interested as s04 is one of my favorites.

 

[SkyBlue]

I’ve just brewed a Hobgoblish ale and used S04 which fermented down from 1044OG to 1010FG in less than six days (77% attenuation). The beer was very clear and the yeast had settled so I decided to keg it early so I can get my next brew on! I’ve never Kegged a beer that early so will be interested to see whether it affects the quality.

 

[Justin Dean]

Intresting

 

[Sandimas]

I’ve just brewed a Hobgoblish ale and used S04 which fermented down from 1044OG to 1010FG in less than six days (77% attenuation).

I'm going to have a further dig into my brewing records (they're on another PC), when I started this thread I just assumed beers are light and dark but of course there is everything in between. I wonder at what point S-04 starts to reduce it's attenuation? My original posting was based on the results of jet-black beers like Porters, I wonder what happens with darker but not black beers like Hobgoblin? I have made it before and probably used S-04.

 

[Rogerh]

Just kegged a Hobgoblin style using S-04. SG 1.049, FG 1.009. Attenuation approx 81% (figures from Brewfather) A landlord clone brewed a while back gave an apparent attenuation of 81.3%. Fermentation temps were a fairly steady 19.5*C

 

[foxy]

This is well worth a read on attenuation.
http://braukaiser.com/documents/Effects_of_mash_parameters_on_attenuation_and_efficiency.pdf