Author Topic: Attenuation/High FG  (Read 774 times)

Offline BeerInTheHand

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Attenuation/High FG
« on: December 11, 2015, 05:51:50 AM »
Hey all, long time lurker, finally decided to join up. I'm manage a LHBS so I'm usually the one giving out advice to people, but this is something I was more so seeing if anybody had ever done a similar grist bill to see if I'm on par with my FG. My question is regarding an Imperial Stout we brewed recently that seems to have a high FG. Part of me thinks that based on the amount of roasted/specialty malts that we used this sounds about right but at the same time it seems higher than I was expecting. Here's the recipe specifics:

14lbs Maris Otter
.75lb C80
.75lb Special Roast
1.25lbs Chocolate Wheat
1lb American Roasted Barley
.5lb American Black Patent
1lb Flaked Oats
1lb Flaked Barley
.25lb(ish) Rice Hulls

Mashed at 153 for 60min.
Batch sparged with 180 degree water

2.5oz @60min EKG for 33IBU

2 WLP007 PurePitch pouches (didn't have time for a starter)

Now here's the kicker... I don't have an OG, we drank a little too much while brewing and took a reading but never wrote it down  :-\. My wife and I think it was around 1.089ish. But the current gravity is sitting at 1.028. I'm well aware of the percentages of roasted/specialty malts and we were trying something different (it tastes fantastic by the way). I just feel like .028 seems a little on the high side. In the past when we brewed a similar beer using a less attenuative yeast (WLP005) it got down to 1.022. Anyhow, the plan is to transfer this on top of some espresso roast coffee this weekend and hopefully keg it by sometime next week.

Thanks in advance for any insight!

Offline dmtaylor

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Re: Attenuation/High FG
« Reply #1 on: December 11, 2015, 02:12:40 PM »
Welcome to the forum!

Is your mash thermometer recently calibrated?  Is it possible you mashed hotter than 153?

What were your fermentation times and temperatures?  Did you rack to secondary?  You should never rack blindly at X number of days but rather need to wait until you are positive that fermentation is done.  Or better yet, never rack at all.
Dave

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Offline BeerInTheHand

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Re: Attenuation/High FG
« Reply #2 on: December 11, 2015, 02:19:47 PM »
Thermometer is good, I checked it recently. It's still in primary, this coming Sunday will be 2 weeks, been fermenting around 70°. I don't secondary beers unless I'm adding something to them or aging for prolonged periods. Last night was the first gravity reading I had taken, after seeing how high it was I swirled the carboy to rouse the yeast and plan on seeing what it looks like this weekend. Every other time I've used 007 it has attenuated down in well under a week, that's why I find this odd. I'm still wondering if its the grain bill.

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Offline HoosierBrew

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Re: Attenuation/High FG
« Reply #3 on: December 11, 2015, 02:27:07 PM »
I'd add that I agree with your idea on the high % of roasted/specialty malts driving up FG a bit as part of the issue. With the uncertainty about your OG, who knows? Maybe you were several points higher and might explain the FG a little further. Lastly, I think the 2 packs of pure pitch is an underpitch for a beer upwards of 1.100 OG. That's probably the last piece of the puzzle. Did you oxygenate pretty thoroughly ?
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Offline Joe Sr.

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Re: Attenuation/High FG
« Reply #4 on: December 11, 2015, 02:59:36 PM »
Bigger beers can also take longer to hit final gravity.  Two weeks is usually long enough for most beers, but there's no harm in patience at this point.

I don't expect you'll go a lot lower, but you might still drop a few points.
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Offline BeerInTheHand

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Re: Attenuation/High FG
« Reply #5 on: December 11, 2015, 03:29:58 PM »
I'd add that I agree with your idea on the high % of roasted/specialty malts driving up FG a bit as part of the issue. With the uncertainty about your OG, who knows? Maybe you were several points higher and might explain the FG a little further. Lastly, I think the 2 packs of pure pitch is an underpitch for a beer upwards of 1.100 OG. That's probably the last piece of the puzzle. Did you oxygenate pretty thoroughly ?

I agree that 2 packs of yeast is a little on the low side, but I don't think it was enough for it to stall fermentation. There was krausen and full activity within 6hrs of pitching the yeast. I did hit it with pure oxygen prior to pitching.

Bigger beers can also take longer to hit final gravity.  Two weeks is usually long enough for most beers, but there's no harm in patience at this point.

I don't expect you'll go a lot lower, but you might still drop a few points.

If I was using a different yeast I would tend to agree that maybe it needs more time. But every time I've used 007 its been an absolute beast and finished off in 3-4 days. I've only had one other beer take more than 2 weeks to hit FG and it was a 10.2% Belgian Dark Strong, even then at 2 weeks it was down to .013 and ended up finishing at .011.

As far as the OG is concerned we are 90% sure it was mid to upper 80's.

So the general consensus is that it seems like it might be a little on the high side even with that grain bill? I'm contemplating hitting it with some more yeast if by Sunday its not any lower.

Offline denny

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Re: Attenuation/High FG
« Reply #6 on: December 11, 2015, 04:39:59 PM »
Bigger beers can also take longer to hit final gravity.  Two weeks is usually long enough for most beers, but there's no harm in patience at this point.

I don't expect you'll go a lot lower, but you might still drop a few points.

Just what I was gonna say, too.  You may get a bit more out of it, but it's pretty much done.
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Offline BeerInTheHand

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Re: Attenuation/High FG
« Reply #7 on: December 11, 2015, 07:10:12 PM »
Alright you guys are saying what I was leaning towards. I'll check it this weekend and see where it's sitting and probably move forward with it. Thanks for the input!

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Offline BeerInTheHand

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Re: Attenuation/High FG
« Reply #8 on: December 14, 2015, 06:17:38 AM »
Update:

Well, took another reading today, hasn't budged. So we racked it onto some coffee beans and it'll be making its way to a keg in a couple days.