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-   -   I can't believe I'm about to post this... (http://www.homebrewtalk.com/f163/i-cant-believe-im-about-post-386930/)

JLem 02-03-2013 01:42 PM

I can't believe I'm about to post this...
 
...but I have an unexpected high "final" gravity reading and I'm not sure how to account for it. Note that I did not say that the fermentation is stuck, because I do not think that it actually is. I'm just surprised that the gravity is not lower. Here're some details:
  • Foreign Export Stout
  • All-Grain
  • OG 1.062
  • Current gravity: 1.024 (via calibrated hydrometer )
  • Brewed on 1/17/13
  • aerated 20 minutes with aquarium pump and air stome
  • Pitched a healthy starter of wlp001
  • fermentation looked great - took off within 12 hours, had a nice foamy krausen
  • fermented at 64F for first 10 days...warmed up to 68F since then

74% Maris Otter
8% Roasted Barley
6% Caraamber
6% Crystal 150L
4% Chocolate malt
2% Black malt

mashed at ~152F

I expected the beer to be down lower - closer to 1.014-1.016. Even the "Imperial Porter" I brewed last year went from 1.090 to 1.020. I am not overly worried - I tasted the hydrometer sample and it was good. More or less just curious if I should expect a lower gravity given my recipe/process. Or are all those dark and crystal malts leaving a lot of unfermentables in there? By all accounts it seems like it should be done fermenting. I was just shocked when I took the hydrometer reading this morning.

Pappers_ 02-03-2013 01:50 PM

The mysterious ways of yeast . . .

It seems like you've covered all the bases, it should be much lower. Two thoughts:

I don't know Caraamber, but added to the Crystal 150 you've got 12% cara/crystal, which would bump your fg up

I wonder if your hydrometer was being help up (bouyed up) by CO2 in the sample? Maybe take another sample and let it sit out for a few hours and then read it.

JLem 02-03-2013 01:54 PM

Quote:

Originally Posted by Pappers_ (Post 4859392)
The mysterious ways of yeast . . .

It seems like you've covered all the bases, it should be much lower. Two thoughts:

I don't know Caraamber, but added to the Crystal 150 you've got 12% cara/crystal, which would bump your fg up

I wonder if your hydrometer was being help up (bouyed up) by CO2 in the sample? Maybe take another sample and let it sit out for a few hours and then read it.

Good point about the crystal - I tend not to use a lot of crystal malt, so I have little experience with its effects on FG. This was a recipe I got from the good folks at Snake River Brewing Company, so I tried not to stray too far from the original. But still, I feel like it should be lower and I'm pretty confident in my process, so I can't really account for it.

I'll try leaving a sample out like you suggested. Maybe I just misread this hydrometer too - I hadn't had my morning coffee yet!

aiptasia 02-03-2013 01:59 PM

The roasted grain amounts would be my guess, too. I'm sure it's a perfectly great beer though. :)

beergolf 02-03-2013 02:49 PM

I agree that it probably is all the roasted grains. It might just not go any lower. I did a stout with a lot of roasted grains and if I remember correctly it also finished high. Somewhere in that range.

Johnnyhitch1 02-03-2013 03:01 PM

Quote:

Originally Posted by JLem (Post 4859405)
Good point about the crystal - I tend not to use a lot of crystal malt, so I have little experience with its effects on FG. This was a recipe I got from the good folks at Snake River Brewing Company, so I tried not to stray too far from the original. But still, I feel like it should be lower and I'm pretty confident in my process, so I can't really account for it.

I'll try leaving a sample out like you suggested. Maybe I just misread this hydrometer too - I hadn't had my morning coffee yet!

Seems like you know someone over in the brewery. Does your buddy get it that low? Does seem like a decent amount of crystal but in something like this i would think you need it but could also get down to .20-21

I would think like pappers also said possibly co2 buoy...?

Was is a fresh vial or slurry?

RiverCityBrewer 02-03-2013 03:04 PM

I also agree that the roasted and caramel malts are what kept your FG high... 26% of the malts in the recipe have limited fermentability which likely account for what you are seeing.

John Palmer explains it better than I do here: http://www.howtobrew.com/section4/chapter20-1.html

Hermit 02-03-2013 03:18 PM

Orfy has a mild recipe posted that I make frequently. Just for comparison. It has 22% c 60. It also has 4% chocolate. Not in the recipe but I added 1% black patent. The two most recent batches I mashed a little higher than you but my temp control sucks and I have to add heat and stir so this is a big variable for me.

First one dropped from 1.040 to 1.016. Second one from 1.038 to 1.014. You started higher but had half the caramel malts.

ncbrewer 02-03-2013 03:52 PM

Quote:

Originally Posted by Pappers_ (Post 4859392)
I wonder if your hydrometer was being help up (bouyed up) by CO2 in the sample? Maybe take another sample and let it sit out for a few hours and then read it.

There's a good explanation of the CO2 effect by AJ Delange in this thread:
http://www.homebrewtalk.com/f128/doe...ravity-286783/

JLem 02-04-2013 08:51 PM

Quote:

Originally Posted by Johnnyhitch1 (Post 4859634)
Seems like you know someone over in the brewery. Does your buddy get it that low? Does seem like a decent amount of crystal but in something like this i would think you need it but could also get down to .20-21

I would think like pappers also said possibly co2 buoy...?

Was is a fresh vial or slurry?

I actually don't know anyone at the brewery - I simply emailed them for the recipe and one of the brewers was kind enough to send along their Excel brewsheet. According to the specs he sent me...their beer starts at 16 Plato, which is 1.065 SG and is 6% ABV. According to my calculations this would put an FG at 1.019 - 1.020, so I guess I am not as far off as I thought I might be...though my OG was a little lower (which I knew, but I was trying to hit an ABV of 6% and was thinking I would get an FG of 1.014 or so).

I took a sample out this afternoon and will let it sit out for a while before I take another gravity reading.

The yeast I used was a starter built up from a new vial.


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