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Author Topic: Big beer OG Misses  (Read 1762 times)

Offline yso191

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Big beer OG Misses
« on: August 05, 2015, 06:29:41 pm »
I need to figure out what is going on.  I hit my numbers consistently with average gravity beers.  But every time I attempt a big beer I miss my numbers - sometimes by a lot. 

Today I brewed a RIS which was supposed to be 1.092 OG.  I took a pre-boil gravity and it showed 10 points lower than predicted so I added all the DME I had (about 13 oz.).  Even with that the OG is sitting at 1.077!

The grain crush was good.  Brun'water predicted a pH of 5.5.  My temperature held steady in the mash at ~155*.  It was an hour mash.  I planned a 90 minute mash but was running short on time so I kept it to an hour. 

I'm at a loss.  Any ideas?

The good news is that even when I miss my OG the beer still tastes good.  :)
« Last Edit: August 05, 2015, 06:32:27 pm by yso191 »
Steve
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Offline HoosierBrew

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Re: Big beer OG Misses
« Reply #1 on: August 05, 2015, 06:37:10 pm »
Was your final volume a little higher than expected ?  The DME should have made up most of that deficit, assuming 5 gallons. Could your FG reading have been stratified? I know it's easy to get a stratified reading after cooling to pitch temps.
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Offline yso191

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Re: Big beer OG Misses
« Reply #2 on: August 05, 2015, 07:16:26 pm »
I take the sample from the hoses that go from the BK to the fermenter.  So it has a lot of trub in it.  The wort is not yet to pitching temp.  I may take another sample once it gets there.
Steve
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Offline a10t2

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Re: Big beer OG Misses
« Reply #3 on: August 05, 2015, 07:21:22 pm »
What was the mash efficiency? Are you compensating for the loss in efficiency on bigger beers?

For a beer that big I would only be expecting ~68% lauter efficiency on my system.

The next thing I'd try would be measuring pH to verify the calculations.
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Offline hopfenundmalz

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Re: Big beer OG Misses
« Reply #4 on: August 05, 2015, 07:27:41 pm »
My efficiency goes down with really big beers as one would expect.

The one I made that was at 1.115, it was a batch sparge, I ran some 1.040ish wort into a 10 gallon kettle I have, then boiled it hard until it was over target, added into the main batch. No small beer on that batch.
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Offline yso191

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Re: Big beer OG Misses
« Reply #5 on: August 05, 2015, 07:52:01 pm »
My efficiency goes down with really big beers as one would expect.

The one I made that was at 1.115, it was a batch sparge, I ran some 1.040ish wort into a 10 gallon kettle I have, then boiled it hard until it was over target, added into the main batch. No small beer on that batch.

That may be the issue.  I wonder if Beersmith compensates for the loss in efficiency of a big beer.  Maybe it is a setting I can manipulate.
Steve
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Offline Stevie

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Re: Big beer OG Misses
« Reply #6 on: August 05, 2015, 08:00:20 pm »
It is something you will learn as you brew on your system. I get about 60-63% on beers 10% and over. One thing you can do is sparge more and boil for 120 minutes. I do this frequently and it helps a bit.

The best choice in my opinion is to partigyle.

Offline yso191

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Re: Big beer OG Misses
« Reply #7 on: August 05, 2015, 08:33:10 pm »
Yep, I just learned something.  I plugged 62% in the efficiency field and boom - 1.076 predicted.  Now I know.  I've been keeping it at 75%.

Thanks all!
Steve
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Offline a10t2

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Re: Big beer OG Misses
« Reply #8 on: August 05, 2015, 08:48:20 pm »
If you're batch-sparging, use this: http://seanterrill.com/batchsparge
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Offline yso191

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Re: Big beer OG Misses
« Reply #9 on: August 05, 2015, 08:58:41 pm »
I feel like whacking myself on the forehead.  This is something I should have known.
Steve
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“Fallacies do not cease to be fallacies because they become fashions.” ― G.K. Chesterton