Author Topic: stuck at 1.020  (Read 2450 times)

Offline curnes

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stuck at 1.020
« on: November 20, 2012, 09:22:22 PM »
Greetings,
My buddies and I regularly brew 15 gallons of all grain ales and usually have a starting gravity in the range of 1.060.  As consistently, our fermentation seems to always stop between 1.020 and 1.019.  Occasionally we get it to ferment a bit lower, to 1.016 or so.  Our beer tastes good but seems to be a bit "starchy."  We usually mash at 149, then raise the temp to 155, then raise it again to 165 and sparge for 60-90 minutes with boiling water.  We also use about 3/4 gallon of yeast starter.  I should mention that we our grain bill is usually about 30lbs of 2row and a couple of pounds of crystal 60.  Hops can vary.

Any suggestion as to how to get our final gravity down a bit for a dryer beer?  I would be happy with something between 1.015 and 1.010.
Cameron
McMinnville, OR

Cameron

Offline thetooth

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Re: stuck at 1.020
« Reply #1 on: November 20, 2012, 10:22:14 PM »
Sparging with boiling water is not a good plan.  You are likely extracting harsh tannins, which may or may not be the "starchy" flavor you are referring to.  Whether it is a contributor to this issue or not, I highly recommend sparging with boiling water.

Have you ever tried doing a simple infusion mash.  Basically a rest around 152 degrees for about an hour, then sparge with around 170-ish water?  That's pretty much all I do (I'll go lower to 148-ish for more attenuation and up to 156 for beers where I want more body).


Offline oly

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Re: stuck at 1.020
« Reply #2 on: November 21, 2012, 12:30:48 AM »
I'm sure thetooth meant:  I highly recommend "NOT" sparging with boiling water.  :)

You'll do much better to keep the grainbed < 170F which usually works with sparge water at ~ 185F, so as not to pick up tannins.

What yeast are you using? That may be a contributor if you're using a low attenuating yeast. Something like US05/1056/WLP001 should get you to 1.012 with that grainbill. Also, you might check on MrMalty.com about the appropriate starter size, to see if 3 quarts is sufficient for your 15gals at 1.060. You might  need a bigger starter.

I also agree with thetooth that, with your grainbill you might as well do single infusion around 150-152 and baseline your beers' FG that way.
« Last Edit: November 21, 2012, 12:37:27 AM by oly »

Offline jeffy

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Re: stuck at 1.020
« Reply #3 on: November 21, 2012, 04:16:20 AM »
A common cause of underattenuation is the lack of oxygen in the cooled wort.  How are you aerating it?
Jeff Gladish, Tampa (989.3, 175.1 Apparent Rennarian)
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Offline thomasben

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Re: stuck at 1.020
« Reply #4 on: November 21, 2012, 05:37:59 AM »
Dealt with this problem for two years. Now I have an 02 system. Beers are fermenting completely now. Totally worth it


Offline euge

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Re: stuck at 1.020
« Reply #5 on: November 21, 2012, 07:08:03 AM »
Sometimes the paper in the hydrometer will shift after being jostled around. You might consider checking it with distilled 60* water.

That also seems like a lot of yeast for 15 gallons. How are you making the starter? Your yeast might not be as optimum as thought. Also the type of yeast is important. Some are done at higher gravities.
The first principle is that you must not fool yourself, and you are the easiest person to fool. -Richard P. Feynman

Offline davidgzach

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Re: stuck at 1.020
« Reply #6 on: November 21, 2012, 07:35:54 AM »
I think you have it covered here:
1) Evaluate yeast strain and amount being pitched.
2) Make sure you are aerating very well.
3) Try not sparging with boiling water. (I do this and have not had a problem with 10G)
4) Try a single infusion mash without mashout. (Actually, if you are raising to 165F and then sparging with boiling water, this could be it.  That means your mash is probably getting past 180F+.  I'm getting to mash out temps with boiling water from ~150F)
5) Double check your hydrometer.

It's got to be in there somewhere.....

Dave
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Offline a10t2

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Re: stuck at 1.020
« Reply #7 on: November 21, 2012, 07:49:58 AM »
5) Double check your hydrometer.

Calibrating your hydrometer(s) and thermometer(s) should be Step 1. Determine that you have a problem before you try to fix it.
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Offline tygo

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Re: stuck at 1.020
« Reply #8 on: November 21, 2012, 07:51:58 AM »
Would you happen to be using a refractometer to test the FG?
Clint
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Offline davidgzach

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Re: stuck at 1.020
« Reply #9 on: November 21, 2012, 09:06:43 AM »
Would you happen to be using a refractometer to test the FG?

That's a good one....
Dave Zach

Offline denny

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Re: stuck at 1.020
« Reply #10 on: November 21, 2012, 09:58:36 AM »
Sparging with boiling water is not a good plan.  You are likely extracting harsh tannins, which may or may not be the "starchy" flavor you are referring to. 

It's the pH, not the temp, that's the culprit in tannin extraction.  If not, no one could do decoction mashes.
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Offline thetooth

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Re: stuck at 1.020
« Reply #11 on: November 21, 2012, 10:18:58 AM »
I'm sure thetooth meant:  I highly recommend "NOT" sparging with boiling water.  :)

Oops... that is what I meant.  Do NOT sparge with boiling water.  LOL

Sorry for any confusion there.

Offline thetooth

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Re: stuck at 1.020
« Reply #12 on: November 21, 2012, 10:28:21 AM »
Sparging with boiling water is not a good plan.  You are likely extracting harsh tannins, which may or may not be the "starchy" flavor you are referring to. 

It's the pH, not the temp, that's the culprit in tannin extraction.  If not, no one could do decoction mashes.

That's an interesting point, Denny.  As I understand it, both PH and Temp are factors... but that does lead to questions about how it isn't an issue in decoction mashing.

From How to Brew: http://www.howtobrew.com/section3/chapter17.html

Quote to note from chapter:
"Sparging is the rinsing of the grain bed to extract as much of the sugars from the grain as possible without extracting mouth-puckering tannins from the grain husks. Typically, 1.5 times as much water is used for sparging as for mashing (e.g., 8 lbs. malt at 2 qt./lb. = 4 gallon mash, so 6 gallons of sparge water). The temperature of the sparge water is important. The water should be no more than 170°F, as husk tannins become more soluble above this temperature, depending on wort pH. This could lead to astringency in the beer."

Offline euge

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Re: stuck at 1.020
« Reply #13 on: November 21, 2012, 10:29:47 AM »
I believe for batch-spargers boiling water presents little risk. Fly sparging may be another matter as I have no practical experience in this area.
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Offline denny

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Re: stuck at 1.020
« Reply #14 on: November 21, 2012, 11:16:56 AM »
That's an interesting point, Denny.  As I understand it, both PH and Temp are factors... but that does lead to questions about how it isn't an issue in decoction mashing.

From How to Brew: http://www.howtobrew.com/section3/chapter17.html

Quote to note from chapter:
"Sparging is the rinsing of the grain bed to extract as much of the sugars from the grain as possible without extracting mouth-puckering tannins from the grain husks. Typically, 1.5 times as much water is used for sparging as for mashing (e.g., 8 lbs. malt at 2 qt./lb. = 4 gallon mash, so 6 gallons of sparge water). The temperature of the sparge water is important. The water should be no more than 170°F, as husk tannins become more soluble above this temperature, depending on wort pH. This could lead to astringency in the beer."

For one thing, John is talking about fly sparging .  The reason you can do decoction mashes is because the mash pH is low (see the part I bolded above).  The real issue in tannin extraction is the pH getting above 6.  It if stays in the proper range (as it almost always does in batch sparging) the risk of tannin extraction is very low to non existent.
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