Author Topic: Gravity consistently off by 10 points  (Read 2094 times)

Offline Arsuf476

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Gravity consistently off by 10 points
« on: November 05, 2016, 10:07:03 PM »
So as the topic says my gravity has consistently been off by 10 points. Switched from biab to cooler mlt with 1/2" braid bazooka type screen, still off by 10 points.  Tried a protean rest today, no change.
Last couple batches added one campden tablet, crushed of course, no change.
Here is my water report:     http://cityofmhk.com/DocumentCenter/View/37322

I brew mostly English style browns, milds and bitters.  Base grain has been briess pale ale malt, 3.5 l.

Any ideas?

Offline curtdogg

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Re: Gravity consistently off by 10 points
« Reply #1 on: November 05, 2016, 10:43:02 PM »
So as the topic says my gravity has consistently been off by 10 points. Switched from biab to cooler mlt with 1/2" braid bazooka type screen, still off by 10 points.  Tried a protean rest today, no change.
Last couple batches added one campden tablet, crushed of course, no change.
Here is my water report:     http://cityofmhk.com/DocumentCenter/View/37322

I brew mostly English style browns, milds and bitters.  Base grain has been briess pale ale malt, 3.5 l.

Any ideas?
I have the exact same issues.
I have switched from Brew in a bag to a gallon water cooler also.
Everything I've read says there are only a few things to do to fix mash efficiency.
Water chemistry / pH. and
adjust the grind on your mill.

I have just recently sarted to pay attention to my pH and have noticed a few points difference.
I buy and grind my grain at the homebrew shop sometimes running it through the mill twice.
I'm not ready to drop the $$ for a mill yet.
I don't have a water report as of yet but I may start messing with water chemistry in the new year.
I keep telling myself I'll figure it out one day but until then I purchase a little extra grain to make up for my   efficiency.



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Offline kramerog

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Re: Gravity consistently off by 10 points
« Reply #2 on: November 06, 2016, 12:23:42 AM »
Crush and mash pH are probably the most typical reasons for low efficiency.  Mash thickness was probably my biggest initial issue.  After decreasing the mash thickness from 1.25 to 1.5 qt/lb my efficiency went up and became more consistent.  The main reason being that it became easier to find and bust up dough balls as they floated to the surface when there is an excess of water.

Protein rest and campden tablets should not change the mash efficiency.

Offline curtdogg

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Re: Gravity consistently off by 10 points
« Reply #3 on: November 06, 2016, 12:27:00 AM »
Crush and mash pH are probably the most typical reasons for low efficiency.  Mash thickness was probably my biggest initial issue.  After decreasing the mash thickness from 1.25 to 1.5 qt/lb my efficiency went up and became more consistent.  The main reason being that it became easier to find and bust up dough balls as they floated to the surface when there is an excess of water.

Protein rest and campden tablets should not change the mash efficiency.
So basically a thinner mash?
I'm curious how one more quart of h20 helps that?

Denny?

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Offline curtdogg

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Re: Gravity consistently off by 10 points
« Reply #4 on: November 06, 2016, 12:27:39 AM »
Crush and mash pH are probably the most typical reasons for low efficiency.  Mash thickness was probably my biggest initial issue.  After decreasing the mash thickness from 1.25 to 1.5 qt/lb my efficiency went up and became more consistent.  The main reason being that it became easier to find and bust up dough balls as they floated to the surface when there is an excess of water.

Protein rest and campden tablets should not change the mash efficiency.
So basically a thinner mash?
I'm curious how one more quart of h20 helps that?

Denny?

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**One more quart per pound I mean.

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Offline Arsuf476

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Re: Gravity consistently off by 10 points
« Reply #5 on: November 06, 2016, 12:57:19 AM »
I crush pretty fine, using a corona mill, do you think the high ph of my water ~9.4 could be the culprit, if so how so I adjust this, acid malt?

Offline curtdogg

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Re: Gravity consistently off by 10 points
« Reply #6 on: November 06, 2016, 01:22:15 AM »
I crush pretty fine, using a corona mill, do you think the high ph of my water ~9.4 could be the culprit, if so how so I adjust this, acid malt?
Could be. I believe the preffered range is 5.2-5.7. I haven't researched acid malt yet. Stay away from pH stabilizer, the pros  on the forum say it's no good.
I've read about starting with distilled water and building your water up to the style your brewing.
Maybe you can get some tips from your local brewery on how to deal with your water.

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Offline Bob357

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Re: Gravity consistently off by 10 points
« Reply #7 on: November 06, 2016, 02:45:52 AM »
I crush pretty fine, using a corona mill, do you think the high ph of my water ~9.4 could be the culprit, if so how so I adjust this, acid malt?

9.4pH is way out there. With a pH that high I'd guess there is plenty else wrong with your water as well. Probably the best thing you could do is use RO water. Most super markets have machines that dispense RO water for 35 or 40 cents per gallon. A simple treatment to RO would be to add about a tsp of gypsum to your strike water for a 5 gallon batch. If you are using any dark crystal or roasted malts, steep them instead of mashing them. That should get you in the ball park. If you want to get more elaborate Bru'n water is a great tool for water adjustment. 
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Offline bboy9000

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Re: Gravity consistently off by 10 points
« Reply #8 on: November 06, 2016, 05:16:29 AM »
Calibrate every vessel by taking a known 1 gallon pitcher, filling  each vessel 1G at a time and marking the kettle or whatever by scratching it or marking a line.  Mark he sides of your kettles, fermentors and mash paddles. 
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Offline narcout

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Re: Gravity consistently off by 10 points
« Reply #9 on: November 06, 2016, 02:41:36 PM »
http://cityofmhk.com/DocumentCenter/View/37322

Your water isn't terrible, but if you aren't making any adjustments I bet your mash pH is higher than optimal, especially on your lighter beers. 

Download a copy of Bru'n Water, fill it out using the last recipe your brewed, and see where your estimated mash pH comes out.

I just did that using your water profile and the recipe I brewed Friday night, and the estimated mash pH was 5.79.  Depending on the style, you want to be down between 5.2 and 5.5.  You could fix this with acid, acid malt, darker malts, or additional calcium (your water is pretty low in calcium, and you'll probably want to bump that up regardless)

https://sites.google.com/site/brunwater/

Be sure to read the Water Knowledge tab at the end.

Let us know if you need any help with the adjustments.


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Offline dmtaylor

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Re: Gravity consistently off by 10 points
« Reply #10 on: November 06, 2016, 03:14:12 PM »
I crush pretty fine, using a corona mill, do you think the high ph of my water ~9.4 could be the culprit, if so how so I adjust this, acid malt?

9.4pH is way out there. With a pH that high I'd guess there is plenty else wrong with your water as well. Probably the best thing you could do is use RO water. Most super markets have machines that dispense RO water for 35 or 40 cents per gallon. A simple treatment to RO would be to add about a tsp of gypsum to your strike water for a 5 gallon batch. If you are using any dark crystal or roasted malts, steep them instead of mashing them. That should get you in the ball park. If you want to get more elaborate Bru'n water is a great tool for water adjustment.

pH was my initial thought.  The water looks fine but a pH of 9.4 is crazy high!  You should either get some 88% lactic acid and add a few drops of that to bring mash pH down, or learn how much acidulated malt to add to every batch for the same purpose.  Measure your mash pH.  You are shooting for 5.3 average or a range of 5.2 to 5.5.  If it is much above 5.5 then this will hurt your efficiency, and at this high mash pH you might also extract tannins which will lead to an odd astringent mouthfeel in the final beer, which dries out your mouth like it's full of cotton.  Look for those things and see if it makes sense.

I would recommend the opposite of Bob with respect to dark roasted malts, and mash but not just steep.  If mash pH is too high, then dark roasted malts would be good to include in the mash as they will help to bring mash pH down towards the magical 5.3 desired.  Crystal malts also help to reduce mash pH.  If you ever do a batch without specialty malts, then additional calcium or lactic acid or acidulated malt additions will be necessary.
« Last Edit: November 06, 2016, 03:16:28 PM by dmtaylor »
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Offline GS

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Re: Gravity consistently off by 10 points
« Reply #11 on: November 06, 2016, 03:43:55 PM »
Let me throw this into the mix...

Do you boil according to time, or to volume? For instance, on my system my evaporation rate is 1.5 gallons per hour, but I can only achieve that under "perfect" conditions. If there is wind, the boil time increases because the heat gets blown out from under the kettle from time to time, preventing a good consistent rolling boil, which in turn affects the evaporation rate. So, rather than watch the clock, I watch the volume marks on my boil kettle.

Last weekend, it was windy and rainy. My brew area is protected from rain, but not quite protected from wind swirling around. My boil took nearly 2 hours; there were several times when the wind reduced the boil to a simmer for a little bit, but I kept going until I had reached the final volume of wort I was looking for. In addition, I check the gravity during the boil with a hydrometer and keep going until I hit the gravity I want. By watching the rate of evaporation, I can time my hops additions accordingly.

Things like pH and malt crush are certainly important, but I do believe that before you can look at those, your process must be sound.

Offline Bob357

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Re: Gravity consistently off by 10 points
« Reply #12 on: November 06, 2016, 04:21:32 PM »


I would recommend the opposite of Bob with respect to dark roasted malts, and mash but not just steep.  If mash pH is too high, then dark roasted malts would be good to include in the mash as they will help to bring mash pH down towards the magical 5.3 desired.  Crystal malts also help to reduce mash pH.  If you ever do a batch without specialty malts, then additional calcium or lactic acid or acidulated malt additions will be necessary.
[/quote]

Sorry if I wasn't clear Dave, but I meant to steep the dark crystal and roasted malts ir he were to use RO water.
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Re: Gravity consistently off by 10 points
« Reply #13 on: November 06, 2016, 04:40:01 PM »
Crush and mash pH are probably the most typical reasons for low efficiency.  Mash thickness was probably my biggest initial issue.  After decreasing the mash thickness from 1.25 to 1.5 qt/lb my efficiency went up and became more consistent.  The main reason being that it became easier to find and bust up dough balls as they floated to the surface when there is an excess of water.

Protein rest and campden tablets should not change the mash efficiency.
So basically a thinner mash?
I'm curious how one more quart of h20 helps that?

Denny?

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Yeah, I also found that my efficiency went up with a thinner mash.  But I'm curious how you decided you were 10 points off?  What were you comparing to?  The published recipe?  If so, you need to adjust ANY recipe to your own efficiency.  If that was and and you're still off, I'd look at crush next.  Things like pH can make a difference, but a very minor difference.
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Re: Gravity consistently off by 10 points
« Reply #14 on: November 06, 2016, 04:41:33 PM »
I crush pretty fine, using a corona mill, do you think the high ph of my water ~9.4 could be the culprit, if so how so I adjust this, acid malt?

Water pH doesn't really matter...it's mash pH that makes some difference.  You need to check in the mash tun.  Also, you need to get a water analysis before you start messing with pH.  I recommend lactic or phosphoric acid to adjust pH.  It's much more reliable and easier than acid malt.
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