I give up! I need to get trace amounts of O2 out of my beer

[Zenmeister]

Hey everyone, earlier this year I decided to enter some of my brews in home brewing contests. And while I am getting pretty good scores in the 36-39 point range, one consistent criticism continually comes up; all the judges have noted a presence of oxidation in my beer. The first couple I blamed on judges who couldn't tell the difference between oxidation and great flavors! By submittal number five, with apologies to the esteemed judges, I have to admit it has to be me and my process. I really thought I was doing everything right, but well, I guess not. So, I am coming to you for suggestions.
First off, I brew with a Spike 20 Gal Trio system on the hot side. The cold side is a SS Brewtech 17 gallon Unitank, with spunding valve, temp control, etc.
Here is my current process:
On the hot side at this point in time I do very little to control dissolved O2. I do control splashing, aggressive stirring, whirlpool, etc, but nothing really special on this side.
Transfer/chilling is done thru an Exchillerator wort chiller, into the bottom of the Unitank. I do aerate with O2 when adding yeast.
I am very anal on the cold side, with ONE major exception. Heres what I do.

I use the CO2 released during fermentation to purge kegs of O2. I start purging the day after fermentation starts, fill the keg as high as possible with StarSan, use the fermentation to pump StarSan solution completely out of the keg, and continue purging for 6-12 hours after that to ensure as much O2 as possible is removed. I typically purge three kegs or so with this process.​

When fermentation is about 95% complete, I will lock down the spunding valve in order to get the remaining CO2 generated to carbonate the beer.​

Finally, transfer to kegs is a completely closed transfer driven by CO2 from the CO2 tank.​

On the cold side, I now think there are two areas where O2 is getting in.

First off is my dry hopping and gelatin addition. Up til now, I have just opened the lid, dropped the hops in and closed the lid, thinking that there was no way enough O2 was getting in through that five second window.​

Secondly, I wonder if I am getting O2 in my bottling process for the beers for the contest. I use the Blichmann Beer Gun, with 5 seconds of CO2 blast at the bottom of the bottle, then top it off with beer foam filled all the way to the top of the bottle.​

So, while my beer is pretty good, I guess to go that last mile I should get an O2-free dry hopping system. Suggestions for my Unitank (With 3" TC Lid) are welcome.
Any other suggestions as well are welcome.

Thanks

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[AlexKay]

Is all of this for very hop-forward beers (like NEIPAs)? Those really require going the extra mile. If you’re having these problems with English ales, though, there’s probably something else going on.

First I’d try to pin down whether the beer from your kegs is having the same problems, or if it’s just the bottles you’re sending off to be judged. Do you have friends or acquaintances locally that can recognized lightly oxidized beer and will come over for drinks?

I like to place my dry hop charge in an empty keg, purge that keg with fermentation gas, and then transfer into it. This generally requires a floating dip tube in the receiving keg. I haven’t had problems with vegetal tastes, and it eliminates the need to open the keg to dry hop.

For purging, is there really a need to swap kegs? Use the whole fermentation to purge the keg, and slap the spunding valve on the purged keg when you’re ready for that.

Use gravity for your closed transfer instead of tank CO2 — it’s at least a theoretical possibility that your tank has enough of an oxygen impurity to cause a problem.

Make sure you’re using barrier tubing, virtually everywhere. Certainly in your kegerator, certainly to connect kegs for purging.

Final food for thought: when judges sit down to judge an IPA flight, they expect everything but the occasional happy exception to be oxidized.

 

[OleBrewing]

granted I don't brew hoppy beers very often and normally don't dry hop often either, but seems a lot of people are having oxidizing issues that i have never come across in my brews. 35-40 ibus probably the bitterest i have done then dry hopped with whole cones no closed transfer and beer was great; probably best the last few beers spanning a couple of months.

maybe i don't taste the slight off flavors the judges can. i would say do a test on beers you would submit and submit them to your self given bottles time as if they were in transit (maybe shake them every so often) blind taste between a keg pour and bottled pour to see if you notice a difference.

my guess is bottling process.

 

[MicroMickey]

Here's something I found in Homebrew Digest a number of years ago. It gets to the heart of your problem.

Subject: Vitamin C in Beer HBD #2388 4/1997

Just a quick empirical observation on vitamin C in beer.

I wanted to see if my beer was oxidized relative to commercial beer and so measured the ORP* of two samples. I did OK. I then stuck an aeration stone into the sample and gave it a shot of O2. Unsurprisingly the ORP went through the roof. Amused by this I dropped in a vitamin C tablet and the ORP went through the floor - well below where it was originally. I never sat down and did anything even quasi scientific about this (it's on a long list) but the initial observation was that ascorbic acid is a pretty good reducing agent.

*ORP – Oxygen Reducing Potential

A. J. deLange

 

[day_trippr]

I can attest to the apparent effectivity of injecting CO2-purged kegs with a teaspoon of Ascorbic Acid powder dissolved in a minimum amount of warm water (~30 ml has been working well for me) just prior to filling. Since I started doing this back in February I have been routinely having kegs of my hoppiest hazies going many months without evident degradation. It really has been a wonderful revelation...

Cheers!

 

[Brewskey]

I can attest to the apparent effectivity of injecting CO2-purged kegs with a teaspoon of Ascorbic Acid powder dissolved in a minimum amount of warm water (~30 ml has been working well for me) just prior to filling. Since I started doing this back in February I have been routinely having kegs of my hoppiest hazies going many months without evident degradation. It really has been a wonderful revelation...

Cheers!

Do you detect any flavor from the AA? I tried it once and I swear I got something like a kids chewable vitamin flavor from it. I don't think I dissolved it first.

 

[day_trippr]

Not even a hint
But I do ensure it's totally dissolved before injecting the solution...

Cheers!

 

[HighVoltageMan!]

If your just getting started with home brew comps, there is a strategy to competing. One of the most common defect in home brew comps is oxygen ingress and people have a tendency to brew and bottle way too soon for a competition. The beers need to be timed so they are at their best when judged. This also means bottling them at closest possible time to submission deadline.

Your process seems solid, but all beer has a shelf life. A lot of the commercial beers from Europe are almost always oxidize where I live, so it's a big problem for all brewers, both home brewers and pros. Adding ascorbic acid isn't a bad idea, but it works better when combined with a small amount of potassium metabisulfite. I add 550 to 1100mg of PMB when I clear the beer with gelatin. I'm careful not to exceed 10ppm, since this is the threshold for declaring it an ingredient for commercial breweries.

I had an opportunity to take some left overs from a local home brewing comp recently. Out of the case of samples (24), only a handful were not oxidized.

EDIT: Get some older beer from the liquor store and try it out with other beer drinkers. Once you taste and get an idea of an oxidized beer, it will be easier for you o pick up on it. It helps to have another homebrewer or beer lover to pick it out.

 

[Zenmeister]

For purging, is there really a need to swap kegs? Use the whole fermentation to purge the keg, and slap the spunding valve on the purged keg when you’re ready for that.

I currently brew 15 gallons, so I need to have three kegs. Otherwise I would just use one.

I dropped in a vitamin C tablet and the ORP went through the floor

Since I started doing this back in February I have been routinely having kegs of my hoppiest hazies going many months without evident degradation. It really has been a wonderful revelation...

Guys, this sounds like a great idea. I will give it a try on my next brew

 

[Broken Crow]

thinking that there was no way enough O2 was getting in through that five second window.

even 1/2 second is enough..the simple action of opening will cause blending of the inner and outer environment. Definitely get some O2-free dry hopping AND gelatin-addition system....NEVER EVER EVER EVER open it post ferment!
Not to state the obvious, but a surprising number of folk forget to purge their transfer lines.
Do you use a mash cap? ..hot side is important too and one area I'm working on myself.. I'll be watching this thread for that.

 

[HighVoltageMan!]

NEVER EVER EVER EVER open it post ferment!

This is easier said then done, I wish it wasn't. I open my fermenters, but before I open them, I flow co2 into them and out another port into a airlock(I have 2 gas ports on my fermenters). The pressure is lowered to 1-2 psi and then I open the fermenter. The positive pressure is kept on the fermenter until the fermenter is closed up again. It's similar to opening a port on a big conical, there is always positive pressure.

Be able to add hops or clarifiers with adding o2 is really tough, but there are systems out there for that. I just wonder when you add dry hops your not adding oxygen because of the hops themselves.

hot side is important too and one area I'm working on myself

Me too. But I'm starting to wonder if it makes that big of a difference. I know it has very little effect on post fermentation o2 ingress, but its hard to gauge if it really makes a difference overall.

Post fermentation o2 ingress is a never ending battle.

 

[day_trippr]

Post fermentation o2 ingress is a never ending battle.

Makes victory even more sweet

Cheers!

 

[seilenos]

When you bottle for submission do you bottle extra so you can taste what the judges are tasting? I'd recommend at least one extra that you pour on the day of judging and one you open for reference when you get your score sheets back. This also allows you to do a direct compare between keg and bottled.

Direct observation by you on if and what the differences are can go a long way to informing process changes.

 

[HighVoltageMan!]

When you bottle for submission do you bottle extra so you can taste what the judges are tasting?

I do that and it does help. I sometimes wait until I see the judges comments. Most times I really don't care what they have to say, I just want a medal. But if I taste oxidation, I know I screwed up somewhere.

 

[wepeeler]

I'll preface this by saying I transferred beer from fermenter to keg via an autosiphon for almost 6 years and never once had oxidation issues. I now close transfer from a unitank, and my beer does seem brighter than before. Perhaps a slight amount of oxidation was occurring, but not enough to be a blatant flaw in my beer. I've had other issues, but not oxidation...

If judges are picking it up in your bottles it could be a couple of things: beer in your keg might be oxidized to start or oxidizing over time, or you're picking up O2 during bottling. Your process seems sound, except for dry hopping. I used to open my brew bucket and drop in dry hops, but I've since built a hop dropper for my 3" port on my Unitank. Used a sight glass with a butterfly valve and a PRV top to purge with CO2. Might want to look into that, although I think it's overkill and only use it for NEIPAs.

I used to use a Blichmann Beer Gun for bottling, and I think it did a good job overall. I would recommend upping your keg PSI 24-48 hours before bottling, to give your beer a little extra (I always find my bottled beer loses a bit of carb). Purge bottles like you do, then fill, then push a little extra CO2 on top, then cap. Honestly, I find that if I purge my bottles and fill directly from my picnic tap and cap on foam, I'm good to go. I recently entered a comp where the beer sat for 2 weeks before being judged and they poured fine.

Could just be a little oversight on packaging. Good luck!

 

[Skeeter686]

Purge bottles like you do, then fill, then push a little extra CO2 on top, then cap. Honestly, I find that if I purge my bottles and fill directly from my picnic tap and cap on foam, I'm good to go. I recently entered a comp where the beer sat for 2 weeks before being judged and they poured fine.

When bottling from the keg, I cap on foam. However, I've never bothered purging the bottle with CO2 prior to filling, because the beer and foam are displacing the O2. It always seemed a little unnecessary and OCD to purge the bottles if I'm capping on foam.

Does the beer really pick up any noticeable O2 in the brief moment that it enters the bottle and before a layer of foam forms on top?

 

[tdf]

Does the beer really pick up any noticeable O2 in the brief moment that it enters the bottle and before a layer of foam forms on top?

Any dissolved o2 from not purging is dwarfed by the difference in cap on foam vs not. Vinny Cilurzo gathered some good data:
https://www.homebrewtalk.com/threads/great-dissolved-oxygen-demonstration.727193/

 

[wepeeler]

When bottling from the keg, I cap on foam. However, I've never bothered purging the bottle with CO2 prior to filling, because the beer and foam are displacing the O2. It always seemed a little unnecessary and OCD to purge the bottles if I'm capping on foam.

Does the beer really pick up any noticeable O2 in the brief moment that it enters the bottle and before a layer of foam forms on top?

Well, the bottle has O2 in it unless you purge it first. I figure that's how the Beer gun and Tapcooler work, so why not? When I fill growlers, I don't purge first, but I leave ZERO head space. I fill until all the foam is pushed out, and there's only liquid coming out. I leave a little space in bottles because it seems like judges want a commercial look to the bottles.