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Author Topic: FG Variance  (Read 6738 times)

Offline klickitat jim

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Re: FG Variance
« Reply #30 on: January 31, 2015, 12:02:49 pm »
Just cold crashed my Regal Pale Ale and my FG is quite lower than the recipe called for. I'm sure I used the correct amount of grain...what else could cause this? I didn't really want a higher ABV, but I guess there are worse things!

Recipe- OG- 1.056, FG- 1.014 (5.5% ABV)

My Brew- OG- 1.057, FG- 1.008 (6.4% ABV)*

*This is an 85% apparent attenuation.

I say this over and over....just ignore it when a recipe tries to predict FG.  It's so inexact as to be worthless.  If the recipe is correct, it's more luck than anything.
This!

Offline klickitat jim

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Re: FG Variance
« Reply #31 on: January 31, 2015, 12:05:07 pm »

+2. Remember we drink beer, not numbers.  Taste the final product and decide how you feel about it. I like well attenuated beer and I've had beers come in at 1.009-1.008 FG that, while a little lower than targeted, were damn good beers.
+3 i like many beers very dry....some struggle to get there.

Does a low FG always equate to a dry beer regardless of what the OG was?
Usually

Offline flbrewer

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Re: FG Variance
« Reply #32 on: January 31, 2015, 12:06:49 pm »
Ok, I'll stop wondering now and enjoy my awesome dry pale ale!

S. cerevisiae

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Re: FG Variance
« Reply #33 on: January 31, 2015, 12:14:37 pm »
I say this over and over....just ignore it when a recipe tries to predict FG.  It's so inexact as to be worthless.  If the recipe is correct, it's more luck than anything.

+1


Offline HoosierBrew

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Re: FG Variance
« Reply #34 on: January 31, 2015, 12:15:28 pm »
Ok, I'll stop wondering now and enjoy my awesome dry pale ale!

It may not be dry per se, but just a little thinner in body.  I bet it's good.
Jon H.

Offline JT

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Re: FG Variance
« Reply #35 on: January 31, 2015, 12:21:20 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!

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Re: FG Variance
« Reply #36 on: January 31, 2015, 12:35:00 pm »
The AA for your recipe is 75%, which is low.  WLP001 is BRY 96.  BRY 96 is one of the highest attenuating normal ale strains.  Attenuation rates in the eighties are not uncommon with BRY 96.

As I have mentioned many times, a high krausen pitch will always outperform a "fermented out" pitch because the cells are in peak health and do not have to undo the morphological changes that occur at the end of fermentation.  Add in sufficient aeration and a strain with a high attenuation rate, and an AA of 85% is not out of the question.

Are you certain that your mash was not stratified (i.e., hot on the top and colder on the bottom or in the middle)?    A minute of stirring is often not enough to achieve an even temperature throughout the mash, especially if you had small dough balls.

Finally, as others have mentioned, one drinks beer, not numbers.  In time, you will know what to expect AA-wise from a yeast strain in your brew house using your water supply.  That knowledge will allow you to adjust your grist and mash profile to push AA in either direction.


Offline HoosierBrew

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Re: FG Variance
« Reply #37 on: January 31, 2015, 01:08:34 pm »
The AA for your recipe is 75%, which is low.  WLP001 is BRY 96.  BRY 96 is one of the highest attenuating normal ale strains.  Attenuation rates in the eighties are not uncommon with BRY 96.

As I have mentioned many times, a high krausen pitch will always outperform a "fermented out" pitch because the cells are in peak health and do not have to undo the morphological changes that occur at the end of fermentation.  Add in sufficient aeration and a strain with a high attenuation rate, and an AA of 85% is not out of the question.

Are you certain that your mash was not stratified (i.e., hot on the top and colder on the bottom or in the middle)?    A minute of stirring is often not enough to achieve an even temperature throughout the mash, especially if you had small dough balls.

Finally, as others have mentioned, one drinks beer, not numbers.  In time, you will know what to expect AA-wise from a yeast strain in your brew house using your water supply.  That knowledge will allow you to adjust your grist and mash profile to push AA in either direction.



+1.  75% for Chico is low. I stir the mash for close to 5 minutes, or as long as it takes to : 1/ ensure no doughballs, and  2/ get a steady temp end to end of the cooler, deep and shallow.  That's the great thing about a trial run on a beer you plan to brew again - more chances to fine tune it.
flbrewer - be extra careful to get a steady mash temp. Assuming you did that, you could always mash a few degrees warmer and maybe increase malts like crystal/caramel or carapils next time to get a higher FG, if you think it needs it. I still say it'll be good.
Jon H.

Offline flbrewer

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Re: FG Variance
« Reply #38 on: January 31, 2015, 01:27:59 pm »
I definitely didn't stir for more than a minute for fear that my temp would be too low. Considering my temp was spot on with a brief stir I'll need a higher strike temp. next time.

Offline flbrewer

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Re: FG Variance
« Reply #39 on: January 31, 2015, 01:29:25 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:
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!

Can you elaborate on this? Are you saying that a higher sparge temp would have extracted more sugars and led to a higher OG?

Offline JT

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Re: FG Variance
« Reply #40 on: January 31, 2015, 02:04:37 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. 

Offline JT

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Re: FG Variance
« Reply #41 on: January 31, 2015, 02:06:08 pm »
But, as my beer is telling me, it really doesn't matter much and still tastes great. 

Offline brewinhard

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Re: FG Variance
« Reply #42 on: January 31, 2015, 02:29:30 pm »
I usually calculate for a couple degree higher strike water temperature so that after I dough in and stir for no dough balls and a uniform mash that my temperature doesn't drop below my anticipated mash temp.  I also have cold treated water on hand to add bit by bit until I get it at the exact temp I desire. 

Since I mash in a cooler it is much easier and less time to add cold water to drop my temp a couple degrees then heat up boiling water and add that back to raise temps by a few degrees.  Has worked for me for years with this process. 

Offline denny

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Re: FG Variance
« Reply #43 on: January 31, 2015, 02:52:01 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.
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Offline denny

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Re: FG Variance
« Reply #44 on: January 31, 2015, 02:52:47 pm »
I usually calculate for a couple degree higher strike water temperature so that after I dough in and stir for no dough balls and a uniform mash that my temperature doesn't drop below my anticipated mash temp.  I also have cold treated water on hand to add bit by bit until I get it at the exact temp I desire. 

Since I mash in a cooler it is much easier and less time to add cold water to drop my temp a couple degrees then heat up boiling water and add that back to raise temps by a few degrees.  Has worked for me for years with this process.

Tip:  use ice cubes instead of water.
Life begins at 60.....1.060, that is!

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The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

"The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts." - Bertrand Russell