Hi, It's a long time since I've been here but the brewing has been going well. However I'm brewing a stout at the moment using S-04 yeast and have a problem with FG. The OG was 1.064 with a target FG of 1.016. It reached 1.024 after a week and stuck. I gave it a stir and upped the brew fridge temp to 22C from 20C. A week later it hasn't budged. I've upped the temp to 25C but I'm not hopeful that it will get going again. I'll give it a few more days to see if it moves but if not should I just bottle it or do I risk gushers?
Stuck Fermentation
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NotSure
Well-Known Member
I've used S-04 a bunch. I had a Dark Mild I made earlier this year with S-04 attenuate to the same level as what you have (~62%). I used the S-04 yeast cake from the Dark Mild for an Oatmeal Stout and got about 80% attenuation. I had no issue with gushers from the Dark Mild, although I admittedly drank them quicker than usual.
The difference between the two brews (apart from the ingredients) was that I mashed a couple of degrees higher with the Dark Mild. So, my guess is that you may have mashed a bit above 67°C. What temperature did you mash at?
The difference between the two brews (apart from the ingredients) was that I mashed a couple of degrees higher with the Dark Mild. So, my guess is that you may have mashed a bit above 67°C. What temperature did you mash at?
Thanks for the input. I mashed at 67 which I stick to religiously for all my brews.
NotSure
Well-Known Member
Hmmmm.... S-04 makes a pretty tight yeast cake. Rousing it is the next step if you didn't do it already. After that, I'd wait a few days or more, take the gravity again, and if there's no movement I'd say it's done.
When I stirred it I made sure to break the yeast cake.
Galena
Landlord.
SO4 is the only yeast I have had stuck fermentations with and never use it now. You could try using some US05 which ferments drier and see if that will take it down some more.
Galena
Landlord.
Yes, thats what I did to get it moving after trying everything else and it did work
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When you took the reading of 1,024 did you degas the sample? Are you really sure your temperature was 67C ? For a stout I would mash at 64C for 1 hour and 68C for 30 minutes, giving the beta and alpha amylase enzymes a fair crack of the whip to produce a fermentable wort.
https://byo.com/article/understanding-enzymes-homebrew-science/
allotment_fox
Regular.
I go with that its will still be a bit on the sweet side and a bit thick but over 5% what does it taste like
PS not sure what your pitch rate of yeast was but could have under pitched if you only used one packet with a 1064 og start I usually add some yeast nutrient for high og starts
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allotment_fox
Regular.
it may be finished as it was suggested all be it sweet but still over 5% a brew with an og 0f 1064 will require more yeast if you used on packet you may have under pitched by 10 Billion cells check on the calculators for pitch rate i tend to use yeast nutrient for strong brews just give it a fighting chance
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I think it is finished, I reckon 99% of blame for a stuck fermentation gets put down to the yeast. When in actual fact it is some error by the brewer in the brewing process. S04 is a good yeast, probably wouldn't use it on a stout myself but it is capable of fermenting out 1,064 @ 15 litres.
One only has to look on Pro Brewers forum and it seems their go to yeast is S04. There are a few things which could go wrong if the yeast wasn't hydrated then it may not have been pitched correctly. The other is temperature, I wish I could categorically state my mash temperature was X degrees.
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