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Author Topic: FG Variance  (Read 6741 times)

Offline flbrewer

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Re: FG Variance
« Reply #45 on: January 31, 2015, 03:48:38 pm »
No.  You're really getting sugars either way, lower temp is more fermentable, higher temp is less fermentable.  Getting the wort to 170 stops enzymatic activity.  If your batch sparge water is 170 degrees, when you mix it with the grist it will be well below that. 
So if your mash fell a bit during the hour wait, and I don't think you added any water to warm it up, with the cooler lid off you vorlauf, drain while temp continues to fall even faster now because the lid is off.  I think  Dennybrew.com elaborates a bit on some temps and end of mash additions. 
Essentially what you're looking to do is raise your mash temp a bit at the end of your mash, being careful not to exceed 170 degrees.

Getting the wort to 170 for 20 min. or so stops enzymatic activity.  Few homebrewers hold the temp that long.  I know I certainly don't!  I also don't worry about exceeding 170.  Maybe I should, but it's never seemed to be a problem.

Not go go down the rabbit hole, but around the 170 figure, are we talking about strike or sparge?

Secondly, are we talking about holding a higher temp. longer?  :o

Offline JT

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Re: FG Variance
« Reply #46 on: January 31, 2015, 04:01:15 pm »
Neither.  170 is ideally the temp you want to elevate your wort to AFTER the hour long mash is complete. 

Offline flbrewer

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Re: FG Variance
« Reply #47 on: January 31, 2015, 04:14:35 pm »
Neither.  170 is ideally the temp you want to elevate your wort to AFTER the hour long mash is complete.

So you're talking about a mashout?

Offline JT

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Re: FG Variance
« Reply #48 on: January 31, 2015, 04:20:19 pm »
Yep, see my original post. 

Offline flbrewer

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Re: FG Variance
« Reply #49 on: January 31, 2015, 04:23:27 pm »
No worries man.  I brewed two APAs that both finished below my expected FG.  84 and 85% attenuation.  Both delicious. 
I'm thinking this occurred because:
1) the gallon or so I added at end of mash before lautering was only 175 degrees.  This hardly moved my mash temp, but during lautering it cooled quite a bit (147 or so) and it took longer than anticipated.  I'm guessing I had a fairly fermentable wort.  I could have used boiling water here to keep my temp up. 
2) my batch sparge water was only 170 degrees, so the same thing occurred there, the 170 degree water didn't boost the grist temp up all that much.   
Those are really the only two things that stood out to me.  In short, a mash out or near mash out may have prevented this... or maybe it wouldn't have.  The beer is still good!

What was the purpose of the gallon you added at the end of the mash prior to sparging? You said you didn't mash out.

Offline JT

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Re: FG Variance
« Reply #50 on: January 31, 2015, 04:25:02 pm »
To equalize the amount of wort I would get from the mash and sparge.  I know that the grain will absorb a good portion of the mash water. 

Offline JT

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Re: FG Variance
« Reply #51 on: January 31, 2015, 04:31:16 pm »
I believe there is a bit of efficiency boost this way.  If I had used boiling water, it would have helped with the temp loss too.  For me, the biggest plus for adding the additional water is that it allows me to collect enough wort to cover the boilcoils in my boil kettle, so I can begin heating my first runnings right away. 

Offline flbrewer

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Re: FG Variance
« Reply #52 on: February 01, 2015, 03:55:36 pm »
Just an update here, bottled today and I now show 1.010. The beer is pretty darn clear for me, perhaps yesterday it was tough to see w/ sediment.

Would priming sugar have anything to do w/ a move from 1.008 to 1.010? If not then I feel better as perhaps it's not as dry as I initially thought.

Offline JT

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Re: FG Variance
« Reply #53 on: February 01, 2015, 03:59:03 pm »
Gravity doesn't go back up unless sugar is added. Don't sweat that 1.008, that's not at all too low. 

Offline flbrewer

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Re: FG Variance
« Reply #54 on: February 01, 2015, 04:28:12 pm »
Gravity doesn't go back up unless sugar is added. Don't sweat that 1.008, that's not at all too low.

Can you confirm which way up and down are on the hydrometer? Which was is "up"?

Offline JT

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Re: FG Variance
« Reply #55 on: February 01, 2015, 04:31:45 pm »
Gravity doesn't go back up unless sugar is added. Don't sweat that 1.008, that's not at all too low.

Can you confirm which way up and down are on the hydrometer? Which was is "up"?
1.010 is higher than 1.008. 

Offline flbrewer

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Re: FG Variance
« Reply #56 on: February 01, 2015, 04:33:52 pm »
So in my case, it raised up bc of the priming sugar. I think I know the answer to this, but it won't permanently raise the FG as the yeast will eat the sugar and bring it back down again. Correct?

Offline JT

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Re: FG Variance
« Reply #57 on: February 01, 2015, 06:07:15 pm »
So in my case, it raised up bc of the priming sugar. I think I know the answer to this, but it won't permanently raise the FG as the yeast will eat the sugar and bring it back down again. Correct?
Yep.