Ask The Brewmasters

This message was posted by a user wishing to remain anonymous

Hey All,
I'm having no success keeping CO² in solution with a 10bbl batch of oatmeal stout. After 6 days of healthy fermentation this brew had slowed. Gravity was .5⁰ lower than expected and holding. I closed the blow off to retain some CO² and conditioning. After 9 days, approximately 7 psi had built up in fermenter. I relieved the pressure and it started rolling again, experiencing a gravity drop from 5.5P to 2.8P over the next 2 weeks. 

Once done, at 2.8P, we turned the tank down to 52⁰F and held for 3 days, then reduced temp to 32⁰F. 2 days later it was transferred into the brite tank and set at 12 psi for carb. I checked the CO² 2 days later and got 2.67 volumes per the Zahm. It all got racked into half barrels. But, as soon as we started pouring it, it immediately flattens out. The CO² break out looks like it's literally boiling and is flat within 60 seconds. I pushed all kegs back into the brite, and there it remains. The CO² just will not stay in solution and I cannot figure out why or how to rectify this. I've attached a few photos of fermenter temperature, Zahm reading, brew log, and current brite tank pressure. I've also attached a video of the CO² breakout after pouring from the sample port. NOTE: This is not a head retention issue...the CO² completely comes out of solution to the point of being flat/still beer. 

Has anyone ever experienced this? If so, I'm interested in learning both root cause and any options for correcting the issue. 

Hello,

I had a somewhat similar issue several years ago with an American wheat ale. It turned out to be a faulty reading on my Zahm, completely my fault as I was not taking good care of it (it was new to me at the time). I thought the beer was carbed and a proceeded to keg it. It was just about completely flat when poured. I ended up putting all of it back in a brite and properly carbing it. Lesson learned. Hope this helps.

------------------------------
Randy Clay
Head Brewer
Lakeville Brewing Company
Lakeville, MN
randy@lakevillebrewing.com
(507) 649-1145
------------------------------

Seems like there is something (maybe carbohydrate complexed with protein?) acting like a nucleation sites. A nucleation site is anything that allows CO2 bubbles to form in the beer.  I believe this is unfiltered, right?  This could be a bugger to figure out, if you can filter some to see if that helps.  Otherwise, Nitro Oatmeal Stout is delicious!  

------------------------------
Troy Rysewyk
Sr Process Innovation Specialist, R&D and Innovation
Molson Coors
Milwaukee WI
(414) 931-3787
------------------------------

Your beer has bubble nuclei. These are sites that facilitate bubble formation. This could be something from the grain, like hydrophobic fungal proteins, or filter media that has broken through, or any of a variety of other microscopic particles.

------------------------------
Roger Barth
Author (with M Farber) of Mastering Brewing Science ISBN 9781119456056
Retired
West Chester PA
------------------------------

Hi there,

We had a beer with cocoa in it, and the foam behaved very similarly.  It sort of poured like a coke- lots of foam and disappearing. 
That combined with a shot gasket in your zahm could be two culprits causing your mystery.  Our zahm is a different style, but we have a black sort of half gasket that was past its due date, and was leading to incorrect high readings.
Good luck, I hope you figure it out.

------------------------------
Erin Dale
Head Brewer
Barkerville Brewing
Quesnel BC
------------------------------

Based on your video, you don't have classic signs of nucleation sites in the beer associated with gushing.  The boiling appearance looks more like rapid foam collapse associated with something that is potently foam-negative, like lipids.  I don't think this explains why your beer is unable to maintain its carbonation level.  Your wort pH looks normal; have you checked your beer pH?

------------------------------
Ashton Lewis
Manager of Training and Technical Support
BSG Craftbrewing
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

I'm somewhat aligned with Ashton here, it seems more like a Foam collapse issue than a reduced carbonation. It's hard to tell from the photos, but to clarify, you measured the carbonation levels as dropping, or they're just perceived that way due to foam collapse?
Do you check carb on both the BBT and the kegs themselves? Is there a chance that the kegs themselves are not under pressure during filling, and could contribute to the reduced carb? Is there any chance there was caustic residue in the kegs?

------------------------------
Cheers!

Sam Thompson
Quality Manager & Innovation Coordinator
Lagunitas Brewing Company
sam.thompson@lagunitas.com
------------------------------

Original Message:
Sent: 05-25-2023 14:27
From: Ashton Lewis
Subject: Carbonation Conundrum

Based on your video, you don't have classic signs of nucleation sites in the beer associated with gushing.  The boiling appearance looks more like rapid foam collapse associated with something that is potently foam-negative, like lipids.  I don't think this explains why your beer is unable to maintain its carbonation level.  Your wort pH looks normal; have you checked your beer pH?

------------------------------
Ashton Lewis
Manager of Training and Technical Support
BSG Craftbrewing
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

Definitely agree with the cocoa fats/ foam collapse points. The video looks like you put a couple drops of something like Fermcap in the glass before pouring the beer in so that could be from the fats in the cocoa.. Also, agree with suggestion to check beer pH. If baking cocoa is the same (similar to) Dutch (alkalized) Cocoa your pH could be out of whack. I've had experience with this and had to abandon cocoa and go with a combination of extract and nibs to get chocolate/cocoa character in the beer.

Best,
Phil

------------------------------
Phil Leinhart
First Key Consulting
Cooperstown NY
(607) 237-4468
------------------------------

Original Message:
Sent: 05-25-2023 22:42
From: Sam Thompson
Subject: Carbonation Conundrum

I'm somewhat aligned with Ashton here, it seems more like a Foam collapse issue than a reduced carbonation. It's hard to tell from the photos, but to clarify, you measured the carbonation levels as dropping, or they're just perceived that way due to foam collapse?
Do you check carb on both the BBT and the kegs themselves? Is there a chance that the kegs themselves are not under pressure during filling, and could contribute to the reduced carb? Is there any chance there was caustic residue in the kegs?

------------------------------
Cheers!

Sam Thompson
Quality Manager & Innovation Coordinator
Lagunitas Brewing Company
sam.thompson@lagunitas.com
------------------------------


Original Message:
Sent: 05-25-2023 14:27
From: Ashton Lewis
Subject: Carbonation Conundrum

Based on your video, you don't have classic signs of nucleation sites in the beer associated with gushing.  The boiling appearance looks more like rapid foam collapse associated with something that is potently foam-negative, like lipids.  I don't think this explains why your beer is unable to maintain its carbonation level.  Your wort pH looks normal; have you checked your beer pH?

------------------------------
Ashton Lewis
Manager of Training and Technical Support
BSG Craftbrewing
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337

As Dana, Ashton and others have eluded to, I feel that the culprit is foam collapse due to the high fat in the Baking Cocoa.  Baking Chocolate is about 50% fat.  Fats, oils and waxes are all major foam inhibitors.  Do you get any tingle/sour/acid flavor on the tongue?  Just enjoy the beer for what it is.

------------------------------
David Gunn
Master Brewer
Kenosha Brewing Co
Kenosha WI
(414) 234-6790
------------------------------

I suggest that both nucleation and lack of head retention are at work. The anonymous poster reported that the beer boiled until decarbonated. The flavor threshold for CO2 in beer is about 0.7 volumes. If the poster could not discern CO2, then the beer was essentially decarbonated. Rapid loss of carbonation is diagnostic of excessive nucleation. But the beer seems to have bubbled vigorously, without gushing. This points to inferior head retention. The chocolate may be the prime suspect for both issues.

Roger Barth, PhD
Professor Emeritus of Chemistry
West Chester University
rbarth@wcupa.edu

Author of
The Chemistry of Beer, The Science in the Suds, Second Edition. ISBN 978-1-119-78333-0
Mastering Brewing Science: Quality and Production. ISBN 978-1-119-45605-6.

________________________________

This e-mail message was sent from a retired or emeritus status employee of West Chester University.


Original Message:
Sent: 5/27/2023 2:30:00 AM
From: David Gunn
Subject: RE: Carbonation Conundrum

As Dana, Ashton and others have eluded to, I feel that the culprit is foam collapse due to the high fat in the Baking Cocoa.  Baking Chocolate is about 50% fat.  Fats, oils and waxes are all major foam inhibitors.  Do you get any tingle/sour/acid flavor on the tongue?  Just enjoy the beer for what it is.

------------------------------
David Gunn
Master Brewer
Kenosha Brewing Co
Kenosha WI
(414) 234-6790
------------------------------

This message was posted by a user wishing to remain anonymous

Thank you so much for taking the time to reply to this.  A few clarifications:
1) The Zahm was broken down, cleaned, and recalibrated as part of of trying to figure this all out. 
2) Bakers Cocoa is the trade name for the dark chocolate roasted malt from one of our maltsters. It is not actual Baker's Cocoa. The only ingredient rich in lipids is the flaked oats at 12% of grist
3)  Unfortunately, neither filtration, nor tapping on Nitro, are options for us here.
4) Current beer pH is 4.2

Thanks again to all. 

Original Message:
Sent: 05-29-2023 13:15
From: Roger Barth
Subject: Carbonation Conundrum

I suggest that both nucleation and lack of head retention are at work. The anonymous poster reported that the beer boiled until decarbonated. The flavor threshold for CO2 in beer is about 0.7 volumes. If the poster could not discern CO2, then the beer was essentially decarbonated. Rapid loss of carbonation is diagnostic of excessive nucleation. But the beer seems to have bubbled vigorously, without gushing. This points to inferior head retention. The chocolate may be the prime suspect for both issues.

Roger Barth, PhD
Professor Emeritus of Chemistry
West Chester University
rbarth@wcupa.edu

Author of
The Chemistry of Beer, The Science in the Suds, Second Edition. ISBN 978-1-119-78333-0
Mastering Brewing Science: Quality and Production. ISBN 978-1-119-45605-6.

________________________________

This e-mail message was sent from a retired or emeritus status employee of West Chester University.



Original Message:
Sent: 5/27/2023 2:30:00 AM
From: David Gunn
Subject: RE: Carbonation Conundrum

As Dana, Ashton and others have eluded to, I feel that the culprit is foam collapse due to the high fat in the Baking Cocoa.  Baking Chocolate is about 50% fat.  Fats, oils and waxes are all major foam inhibitors.  Do you get any tingle/sour/acid flavor on the tongue?  Just enjoy the beer for what it is.

------------------------------
David Gunn
Master Brewer
Kenosha Brewing Co
Kenosha WI
(414) 234-6790
------------------------------

Dear Foam Fomenter,

One solution that may help with your funky foam would be to bench trial propylene glycol alginate.  PGA is a well-established defender of foam and does its thing by combatting foam-negative compounds in beer.  Could be a way to save the day.  You could also check out what a modest tetra hop addition (~5 mg/L) would do for this brew.  If this were my beer, a belt and suspenders approach, using PGA and tetra, would also be on the table.

Cheers,
Ashton

------------------------------
Ashton Lewis
Manager of Training and Technical Support
BSG Craftbrewing
MBAA District Great Plains, Technical Chair
Springfield, Missouri
(417) 830-2337
------------------------------

Original Message:
Sent: 05-30-2023 15:35
From: Anonymous Member
Subject: Carbonation Conundrum

This message was posted by a user wishing to remain anonymous

Thank you so much for taking the time to reply to this.  A few clarifications:
1) The Zahm was broken down, cleaned, and recalibrated as part of of trying to figure this all out.
2) Bakers Cocoa is the trade name for the dark chocolate roasted malt from one of our maltsters. It is not actual Baker's Cocoa. The only ingredient rich in lipids is the flaked oats at 12% of grist
3)  Unfortunately, neither filtration, nor tapping on Nitro, are options for us here.
4) Current beer pH is 4.2

Thanks again to all.

Original Message:
Sent: 05-29-2023 13:15
From: Roger Barth
Subject: Carbonation Conundrum

I suggest that both nucleation and lack of head retention are at work. The anonymous poster reported that the beer boiled until decarbonated. The flavor threshold for CO2 in beer is about 0.7 volumes. If the poster could not discern CO2, then the beer was essentially decarbonated. Rapid loss of carbonation is diagnostic of excessive nucleation. But the beer seems to have bubbled vigorously, without gushing. This points to inferior head retention. The chocolate may be the prime suspect for both issues.

Roger Barth, PhD
Professor Emeritus of Chemistry
West Chester University
rbarth@wcupa.edu

Author of
The Chemistry of Beer, The Science in the Suds, Second Edition. ISBN 978-1-119-78333-0
Mastering Brewing Science: Quality and Production. ISBN 978-1-119-45605-6.

________________________________

This e-mail message was sent from a retired or emeritus status employee of West Chester University.



Original Message:
Sent: 5/27/2023 2:30:00 AM
From: David Gunn
Subject: RE: Carbonation Conundrum

As Dana, Ashton and others have eluded to, I feel that the culprit is foam collapse due to the high fat in the Baking Cocoa.  Baking Chocolate is about 50% fat.  Fats, oils and waxes are all major foam inhibitors.  Do you get any tingle/sour/acid flavor on the tongue?  Just enjoy the beer for what it is.

------------------------------
David Gunn
Master Brewer
Kenosha Brewing Co
Kenosha WI
(414) 234-6790