Author Topic: Gelatin finings and oxidation?  (Read 1114 times)

Offline ryanmarsh

  • 1st Kit
  • *
  • Posts: 1
Gelatin finings and oxidation?
« on: May 04, 2019, 03:43:08 am »
Sorry for the long post. I like clear beer, but recently a couple of my beers from an independent competition came back with comments about oxidation. The beer was definitely oxidized and maybe 3 months old and served directly from a keg. I limit the oxygen exposure post fermentation (so I tell myself) with careful racking and purging of kegs with CO2. However, I fined these beers with gelatin, and prior to that there was no noticeable oxidation.

My gelatin method is to add 1/4-1/2 teaspoon to cold water, let it sit. Then heat it to 160 degrees to dissolved it and pour it hot into the keg (usually precarbonated) then shut the hatch quick. Mix, then wait.

Since there was probably a large amount of dissolved oxygen in the gelatin water, could this have oxidized my beer? Has anyone else had this experience? Obviously it is hard to comment since nobody knows my whole brewing process but I'm just throwing it out there. I haven't noticed any oxidation from things I've bottle carb'd.

Offline tommymorris

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 3485
Gelatin finings and oxidation?
« Reply #1 on: May 04, 2019, 04:26:19 am »
Sorry for the long post. I like clear beer, but recently a couple of my beers from an independent competition came back with comments about oxidation. The beer was definitely oxidized and maybe 3 months old and served directly from a keg. I limit the oxygen exposure post fermentation (so I tell myself) with careful racking and purging of kegs with CO2. However, I fined these beers with gelatin, and prior to that there was no noticeable oxidation.

My gelatin method is to add 1/4-1/2 teaspoon to cold water, let it sit. Then heat it to 160 degrees to dissolved it and pour it hot into the keg (usually precarbonated) then shut the hatch quick. Mix, then wait.

Since there was probably a large amount of dissolved oxygen in the gelatin water, could this have oxidized my beer? Has anyone else had this experience? Obviously it is hard to comment since nobody knows my whole brewing process but I'm just throwing it out there. I haven't noticed any oxidation from things I've bottle carb'd.
Gelatin can oxidize. Was the beer directly from the keg also oxidized? How did you bottle from the keg? That can oxidize also.

Offline ynotbrusum

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 4458
Re: Gelatin finings and oxidation?
« Reply #2 on: May 04, 2019, 05:14:26 am »
It can even oxidize in the mash, but HSA is a myth to some...check into the low oxygen brewing site for keeping oxygen ingress at bay on the cold side with spunding.

http://www.lowoxygenbrewing.com/

Some may consider these methods to be overkill, but it is remarkable what can be achieved at the homebrew level.
Hodge Garage Brewing: "Brew with a glad heart!"

Offline Robert

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 4214
Re: Gelatin finings and oxidation?
« Reply #3 on: May 04, 2019, 05:24:08 am »
The level of dissolved oxygen in the gelatin solution may seem significant, but the total amount added to the batch is going to be negligible.  I've never had this problem with fining.  My method is to introduce finings through the gas port with the PRV pulled, quickly close up and repurge the headspace, which may allow less exposure.  But I'd still suspect the culprit source of oxygen was elsewhere.  If bottled off the keg, that's a more significant opportunity for oxygen exposure. Beer guns and even CP fillers are not very good at purging the bottle and limiting exposure during the fill, so even capping on foam, the damage may already be done.  Like Tommy asked, was the beer direct from the keg similarly oxidized? 
Rob Stein
Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.

Offline BrewBama

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 5274
Gelatin finings and oxidation?
« Reply #4 on: May 04, 2019, 05:28:15 am »
Opening the hatch and pouring in the gelatin as well as the oxygen in the water could have caused the oxidation.

You could try boiling the water, letting it cool, mix the gelatin, and add it to the keg via the in post. You’ll need some sort of syringe attached to a quick disconnect to push it in.

Or, you could just let the keg sit cold until it clears on its own. Choosing a highly flocculant yeast helps.

Gelatin works to a point but there’s no substitute for time IMO. The beer seems to be brighter given time vs gelatin.  But I have had those beers that just wouldn’t clear so I hit them with fining agents.


Sent from my iPad using Tapatalk
« Last Edit: May 04, 2019, 05:31:29 am by BrewBama »

Offline RC

  • Brewmaster
  • *****
  • Posts: 662
Re: Gelatin finings and oxidation?
« Reply #5 on: May 04, 2019, 01:46:38 pm »
My guess is you're getting more O2 ingress from opening the lid than from the gelatin solution itself.

I fine with gelatin pretty much exactly the way you do, but before opening the lid, I attach CO2 to the keg and keep it on continuously at about 1 psi. Then I lock open the PRV, open the lid, dump in the gelatin and quickly shut the lid. The whole time I have the 1 psi of CO2 going. The idea is to maintain positive pressure in the headspace while the lid is open, which (hopefully) minimizes the amount of O2 sneaking in. Once the lid is shut I go to 5psi and purge the headspace thru the PRV for about 30 seconds.

I have never had oxidation issues, but it's rare that a beer is on tap in my house for longer than ~30-40 days.

Offline hopfenundmalz

  • Global Moderator
  • I must live here
  • *****
  • Posts: 10431
  • Milford, MI
Re: Gelatin finings and oxidation?
« Reply #6 on: May 04, 2019, 06:12:23 pm »
The partial pressure of O2 is ~3 PSI, so that is forcing O2 in. I purge the headspace with 30 PSI at least 13 times if the keg was opened.
Jeff Rankert
AHA Lifetime Member
BJCP National
Ann Arbor Brewers Guild
Home-brewing, not just a hobby, it is a lifestyle!

Offline hopsindahood

  • 1st Kit
  • *
  • Posts: 20
Re: Gelatin finings and oxidation?
« Reply #7 on: May 08, 2019, 05:17:55 pm »
When I gelatin fine in keg, I pour the gelatin in after I sanitize, purge fully, then fill the keg from the "out" post and bleed off the co2 from the pressure valve.  Works like a champ and limits the times I open the keg after purging to zero.

Offline Robert

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 4214
Re: Gelatin finings and oxidation?
« Reply #8 on: May 08, 2019, 05:25:50 pm »
When I gelatin fine in keg, I pour the gelatin in after I sanitize, purge fully, then fill the keg from the "out" post and bleed off the co2 from the pressure valve.  Works like a champ and limits the times I open the keg after purging to zero.
But to purge, you have to fill the keg with liquid and push it all out with CO2,  so you clearly have to open the keg once after purging to add the finings.
Rob Stein
Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.

Offline hopsindahood

  • 1st Kit
  • *
  • Posts: 20
Re: Gelatin finings and oxidation?
« Reply #9 on: May 08, 2019, 05:32:48 pm »
But to purge, you have to fill the keg with liquid and push it all out with CO2,  so you clearly have to open the keg once after purging to add the finings.

Doing it that way, yes.

I don't do it that way if I am adding finings to the keg. I purge with co2. A few fills of co2 purges the atmosphere from the keg. The fining also gets homogenized as the keg is filling. Once the keg is full, I do a few more co2 purges before force carbing. I've been doing this for years and often keep kegs for extended periods of time. I've never had an oxidized beer using this method.

Offline Robert

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 4214
Re: Gelatin finings and oxidation?
« Reply #10 on: May 08, 2019, 05:40:17 pm »


But to purge, you have to fill the keg with liquid and push it all out with CO2,  so you clearly have to open the keg once after purging to add the finings.

Doing it that way, yes.

I don't do it that way if I am adding finings to the keg. I purge with co2. A few fills of co2 purges the atmosphere from the keg. The fining also gets homogenized as the keg is filling. Once the keg is full, I do a few more co2 purges before force carbing. I've been doing this for years and often keep kegs for extended periods of time. I've never had an oxidized beer using this method.

IIRC the minimum to purge a keg below acceptable O2 levels by pressurizing and pulling  the PRV is at least 15 cycles at 30 psig, which I figure is a waste of gas, since that still leaves some O2, and it's just easier to liquid purge.  But if your experience is that your method works for you, that's the important thing.  It has occurred to  me to do something like your method.  But I also fill the keg until beer is exiting the gas port, so I'd have to estimate how much of the finings I was losing too....  More than one way to get the job done I guess.
Rob Stein
Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.

Offline BrewBama

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 5274
Re: Gelatin finings and oxidation?
« Reply #11 on: May 08, 2019, 06:42:44 pm »
Here ya go Robert:




Sent from my iPhone using Tapatalk

Offline Robert

  • Official Poobah of No Life. (I Got Ban Hammered by Drew)
  • *********
  • Posts: 4214
Re: Gelatin finings and oxidation?
« Reply #12 on: May 08, 2019, 06:44:19 pm »
Cheers!


(Mind you, if you've filled the keg and then opened it to add finings, 15 cycles at 30 psig on just the headspace is not much of a waste of gas at all.  And I usually don't even go to that extreme, because since I add finings through the gas port rather than the lid, I figure the interface with the atmosphere is minimal.)
« Last Edit: May 08, 2019, 07:05:25 pm by Robert »
Rob Stein
Akron, Ohio

I'd rather have questions I can't answer than answers I can't question.