I have brewed a stout intended to be around 6%. After two weeks the FG is 1.024 but expected to be closer to 1.010.

I found when I made the yeast starter (Giga Yeast 011) the yeast clumped and dropped out really quickly, it seemed like the same thing happened very quickly in the fermenter.

Could it be that I need to swirl the yeast regularly in the fermenter? Any other considerations?

1 Answer 1


Could be yeast issue or 1.024 is the terminal gravity.

Yeast: Even though you had some early flocculation. I doubt this is the cause of the stall. You can try to warm it up a little and get the yeast back in suspension to get it to finish out.

Already at TG: A common mistake with stouts is using a lot of specialty grains. These dark grains have a large portion of unfermentable sugars. Many calculators don't account for this. Also a high mash temp 156°F+ will make it more unfermentable.

Without is having the grain bill, brew process, yeast pitching method etc. It's hard to give a diffinative answer.

  • Thanks, if you care to take a look it's here: beerlad.com/myrecipe/2IOndj9vDZ/Harrowing-Oatmeal%20Stout One thing, the mash wasn't high, however it did take ages to get to a boil (because it was around 0 degrees and we were boiling outside).
    – W4K1NG
    Jul 13, 2018 at 5:01
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    @W4K1NG from what I can tell it looks like that 149°F is critical not to over shoot even by 1 degree. Reason is the first 20-30 minutes or so beta-amylase will do most the work in the mash making a very fermentable wort. In my experience MO produces much more unfermentables than say 2-row base. Also the oats can give a false increase in gravity readings from unconverted starches. Total you about 20% of the grist as specialty grains that tend to have up to half of thier sugars Unfermentable. The MO while a base malt has a measure of unfermentables too. I'd stay it's about as low as it can get. Jul 13, 2018 at 5:33
  • Thanks - Is there a more accurate calculator out there? Intending to make a 6% and coming out at 4% is not ideal.
    – W4K1NG
    Jul 13, 2018 at 6:58
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    I asked a similar question a few weeks ago: homebrew.stackexchange.com/questions/23065/… Jul 13, 2018 at 15:24
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    @W4K1NG any brew calculator that factors mash temp with the grain bill should be pretty close. The error comes into executing the mash perfectly as the program expects. The program also needs a good base line of your mash effieciency for that same process on your system. If the calculator doesn't change FG when entering a wide range of mash temps and times then it doesn't factor them and only assumes an average of the grains. Also grains used for the batch should be updated using the maltsters data sheet for that batch of grains as they do change from harvest to harvest. Jul 15, 2018 at 14:01

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