Natural Conditioning in Keg - The Answer to Mitigating Oxidation?

[ultravista]

I have been brewing NEIPAs lately, beers that darken in the presence of oxygen, or oxidation.

I do not use CO2 to transfer from fermenter (closed transfer) to keg but do take care to limit O2 pickup by limiting splashing and purging.

The more I read about O2 pickup, I am considering keg conditioning with priming sugar to carbonate while scrubbing O2.

Is it plausible that keg conditioning with priming sugar will scrub O2 left in the beer?

The benefits of keg conditioning may also be beneficial to the hop flavor/aroma while at ambient temperature for a few weeks. My theory that is ...

Your thoughts?

 

[brew_darrymore]

That's not a bad idea at all. Adding sugar and restarting fermentation will help take care of most of O2 the beer picked up during transfer.

I suppose you also purge the headspace once the transfer to a keg is done?

 

[ultravista]

I always purge after the lid comes off.

Since I cannot do a closed transfer, the next best thing (I hope) is keg conditioning to carbonate and scrub oxygen. Purely hypothetical at this point, just an idea.

One thing I will stop doing is shaking the crap out of the keg once I add the dry hops (and purging). I'll shake it a couple of times a day to get the hops moving around. While the keg is always purged, I wonder if this too is not a good idea.

 

[GPP33]

Shaking probably doesn’t help anything, especially your quest to keep any remaining O2 out of solution. Has anyone actually done a test to verify the theory that yeast will “scrub” all of the O2 before oxidation takes place? Once the O2 has been tied up in an oxidation reaction I don’t see yeast reducing that reaction and taking it back to an unoxidized state. Could be a good Brulosphy experiment.

What fermenter do you use? I’m sure we could figure out a closed setup for you.

 

[ultravista]

I use a Norther Brewer Big Mouth Bubbler. To delve a little deeper, here is my post boil process.

01) transfer to fermenter through plate chiller
02) oxygenate through a 2 micron stone with bottled O2
03) pitch yeast slurry (saved yeast built w/starter)
04) cap the fermenter and add blow-off house to container w/sanitized water
05) move to temperature controlled fermenter
06) take gravity sample post fermentation (carefully)
07) transfer to keg w/ Fermtech auto-siphon
08) fill from the bottom-up - no splashing filling hose resting @ the bottom of the keg
09) add 1st dry hop mesh container w/hops (300 micron stainless steel mesh dry hopper)
10) cap and purge w/CO2 - leaving CO2 attached
11) shake the keg to keep the hops moving
12) wait 4-5 days @ ambient temperature
13) add 2nd dry hop mesh container w/hops (300 micron stainless steel mesh dry hopper)
14) cap and purge w/CO2 - leaving CO2 attached
15) shake the keg to keep the hops moving
16) wait 4-5 days
17) refrigerate - leaving both dry hop charges in the keg

I am careful throughout the post fermentation process to limit oxygen ingress. As careful as I can ...

I do not have the means (now) to do a closed transfer w/my current equipment.

My NEIPAs, which are most telling of oxidation, aren't bad. I don't brew bad batches, but they do darken over time. My 5 gallon batches last 4-5 months, I am the only one drinking here

So ... I would like to tighten-up the post-fermentation process to further limit O2 pickup. Two things I can think of are:

1) stop shaking the keg
2) naturally carbonate/condition with priming sugar

What other process changes do you recommend?

 

[GPP33]

Siphons suck for keeping O2 away from your beer. I assemble a ball lock quick disconnect bulkhead using a combination of these pieces:


https://www.homebrewing.org/Stainless-Steel-Weldless-Bulkhead-12-NPT-_p_4642.html


https://www.homebrewing.org/Plug-Adapter-14-MPT-x-1932_p_4640.html


https://www.homebrewing.org/34-MPT-X-12-FPT-Hex-Reducing-Bushing-SS304_p_4182.html



This allows me to drain my wort from the bottom of my Fermonster (not sure if it’ll work on your BMB) directly into the beer out post of the keg. I then have a lid which has the same apparatus which gets connected to the gas in post of the keg. The keg has been previously filled with starsan and purged using CO2. This sets up a gravity fed closed loop system that keeps O2 away. You have to pay attention to make sure you get all of the lines filled with Starsan then purged with CO2 but once you’ve done it a couple of times it’s pretty smooth. Once it’s flowing it’s 100% hands off until you have to tilt the fermentor to get those last few drops of beer out, I’ve actually had a couple bigger batches which overflowed the keg into the gas line, no biggie, just disconnect everything and you’re keg is filled and ready for pressure. If I want to cold crash I hook the CO2 up to the lid and give it about .5psi of gas. Before filling the keg I hook up a line and draw a gravity sample off of the bottom, again, without opening or introducing O2.


You’ll have to open something somewhere along the line to get hops in, that’s just the nature of the beast but if you do it when your keg is full it’ll be pretty easy to purge most of the O2 out since the head space is small. I turn my gas up to 30psi and pull the relief valve 12 times letting it fully pressurize between pulls. I did the math and that’s what it takes to exchange 99.9% of the gas which is the purity of your CO2. I usually dry hop in primary now and I do it as quick as I can while switching between the lid with an airlock and a lid with the above mentioned apparatus. When the hops hit the beer they cause a lot of CO2 to come out of solution so it flushes some of the air that got introduced, no way to tell how much though. I just hope for the best knowing that (a) not much air made it in (b) air is only 20% oxygen (c) CO2 is being released to push some of it out and (d) the beer is sitting still so it’s not getting mixed in. I can’t imagine much gets dissolved in the 5 days it’s sitting there before being put in a keg.

 

[madscientist451]

I know some pro breweries add (some of) the dry hops while the fermentation is still active, the beer is still moving in the fermenter somewhat, and introduction of oxygen when adding the hops is mitigated. I haven't tried it yet, but it sounds like the method may be useful in some situations.

 

[ultravista]

I use a 6.5 gallon glass Big Mouth Bubbler .. no port options.

I have used an auto-siphon from the first brew. Maybe I'll use the 'cane' part of the siphon and start the beer movement w/my mouth.

 

[ultravista]

I know some pro breweries add (some of) the dry hops while the fermentation is still active ..

I am going to try this for the next batch, bio-transformation. We'll see how it goes.

 

[Hoppy2bmerry]

I use a 6.5 gallon glass Big Mouth Bubbler .. no port options.

I have used an auto-siphon from the first brew. Maybe I'll use the 'cane' part of the siphon and start the beer movement w/my mouth.

You gonna sanitize your lips and mouth with vodka or something first, right?

 

[GPP33]

I use a 6.5 gallon glass Big Mouth Bubbler .. no port options.

I have used an auto-siphon from the first brew. Maybe I'll use the 'cane' part of the siphon and start the beer movement w/my mouth.

I was picturing plastic. Maybe do the bulkhead trick so you can get a gas in line in the lid and use that to push the beer out of a racking cane. You'd need to find a grommet or something to seal the cane against the lid so it'll hold about a PSI. You'd also need to make sure the lid can't pop off. Maybe it's time to upgrade your fermenter if you are after lower O2 exposure.

 

[HausBrauerei_Harvey]

I started doing this to almost all my beers about 6 months ago, and i think it's a great idea! I dont brew many hoppy beers, but I've done this on my german lagers and belgian ales and I think it makes a difference. I keg like normal, add only about 1/4 the priming sugar needed for a full carb of the beer, purge the headspace and fill the headspace with a good 20psi dose of CO2 then let it condition at 65 for 2-3 weeks.

My reasoning for not doing a full dose of priming sugar is to limit the amount of yeast that gets made again in the keg when it's fermenting out that sugar. doing this I think i'm scrubbing oxygen from the keg and I dont end up with much more junk in the first few pours than I had previously.

 

[GnenieGone]

I know some pro breweries add (some of) the dry hops while the fermentation is still active, the beer is still moving in the fermenter somewhat, and introduction of oxygen when adding the hops is mitigated. I haven't tried it yet, but it sounds like the method may be useful in some situations.

That's the way to go. Helps with post fermentation diacetyl with large DH additions. Gone round and round on the NEIPA forum we but believe carbs in the hops reactivate fermentaion and O2 in the transfer process propagates the process to the diacetyl formation stage. It seems to always appear around day 3-4 post bottling/kegging for us. Fermentaion Day 2-3 DH additions and zero O2 introduction eliminates the issue.

 

[ultravista]

nope.

 

[TheHopfather]

There are a bunch of options to help you limit O2 going into the keg. One of the most popular with a NEIPA is to rack to the keg with a few points of gravity left to go and spund it. This way you don't need to add additional sugar and you can still naturally carbonate the beer.

As for CO2 transfers with your setup I would look at getting the Sterile Siphon Stater from MoreBeer;

https://www.morebeer.com/products/sterile-siphon-starter-threaded-neck-carboys.html

The orange carboy cap that comes with the siphon just so happens to fit pretty perfectly over one of those universal rubber stoppers;

https://www.morebeer.com/products/rubber-stopper-universal-hole.html

Just drill an additional small hole in the bottom of the rubber stopper and you've got the makings of a CO2 transfer system. I used a carbonation cap with a barb on it to replace the mouth piece on the siphon starter, simply because I didn't want to have to take my ball lock connector off my regulator.

https://www.ontariobeerkegs.com/Carbonation_Cap_with_Gas_Barb_p/carb-cap-w-barb.htm

 

[wobdee]

You could add your priming solution to your primary fermenter instead of keg, wait 1-2 hours for it to start up again then transfer to your sanitized purged keg.