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stouts finale gravity finished high

bummer47

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mashed at 158 for about 60 min. estimated gravty 1.073 ended up with 1.077.
estimated finale gravity was 1.019. ended up with 1.028.
question did i mash a little to high. and ended up with a little more unfermentible sugars then planned
i hade a good fermentation temp. pithed the yeast at 68f. airated well. thats the only thng i can figure.
 
My "rough" estimate for a 150F fermentation would yield a FG of about 1.019.  None of the brewing software programs allow for variable mash temps and the resulting attenuation or fermentability of the wort.  There are too many factors to allow accurate calculation.  These include, yeast strain used, mash thickness, mash time (including time to mash out temp which may happen in the boil), temp gradient during the mash,  type of mash (simple, multi-step, decoction, and varients of these, etc.) 
By knowing your system and what attenuation you achieve on your system at various temps, ratio's etc. with the yeast in question, you can graph your results which will give you a good idea. 

In BeerSmith you can copy(duplicate) a yeast and rename it stating a 158F mash and change the attenuation parameter to match your results.  This will give you a better "prediction".

I would estimate a 1.025-1.026 for a 158F mash when fermenting on my system with dry Nottingham yeast so your actual results are "ok".

Fred
 
How's it taste?  1.077 down to 1.028 is 63% attenuation.  If it fermented out and tastes "done" then I'd look at two things.  The ratio of base grains to lower-PPG, highly-roasted grains.  The latter do not ferm out as well, and some stout recipes have a lot of those grains.  And two, the mash temp would affect the fermentability of those base grains.  It's likely a mix of the two.

Had you reached 1.024, that would have been 70% attenuation, totally acceptable for a big stout.  So you're only chasing four points.  No worries, if it tastes OK.
 
What temperature was the initial mash? Was a yeast started made and if so how big? That really is not that many points off. Doing the secondary at that temp should not affect final gravity as that would make fermentation stop.
 
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