Flavor and aroma loss - I can not figure out why this keeps happening!

[mac_1103]

It was open the lid, put your beer in and do two to five spurts and you are good to go.

Yeah well I never said that.

I've searched for it but can't find it

Just ask @VikeMan.

Though I do like your idea of a huge barrel of starsan that you just dunk the keg in and seal. Maybe one of those 50 gallon plastic barrels.

I've got several of those that I use as rain barrels. I didn't find them all that easy to reach down into when I was trying to install spigots close to the bottom. If I was going to use one as a keg dunk tank, I'd probably cut it down to just a few inches taller than the kegs.

 

[Bassman2003]

In context - "Back when I was learning about kegging, the thought did not go that deep about gas laws and mixing. It was open the lid, put your beer in and do two to five spurts and you are good to go."

I never said you did say that. Homebrewing has come a long way in the last twenty years.

 

[Broken Crow]

If I was going to use one as a keg dunk tank, I'd probably cut it down to just a few inches taller than the kegs.

Roughly; It would take a little under 3oz. of Star San to fill one of those barrels.... I could justify that expense. There's a wine-making place a few blocks from me, that frequently sells those barrels prety cheap, but it takes me a long time to do anything and I've already got a full list, but that does sound like it would put my O2 worries to rest....
Any chance you might give it a try yourself? I'd love to know how many kegs could be fully submerged at once.
BTW; Thanks for the link to that chart..and a little further down the thread, the link to dougcz's 'epic post'...very good reading! It's still not the very long O2 purging thread I'm looking for, but it does contain all the background information that my damaged brain has a hard time retaining.

 

[Bassman2003]

I don't know how much the barrel would work better than a fill up as you need to tilt the keg to get the trapped air pocket under the lid out. If you just submerged it I do not know if the air under the lid would necessarily come out very easily. Tilting moves it to the post out from under the lid.

 

[Broken Crow]

Damn! I wish I had pictures of my process, but it takes two hands. Even tilted, because of the bale, I can't get the air out from that last maybe 1/4" side of the lid that remains above the mouth of the keg. That's why I would like to have the entire keg submerged deep enough that I can submerse the lid upside down and then flip it and insert into the corny-mouth completely under the Star San. ....Just to cover all the bases: My current process includes having a bare disconnect on the gas post while filling through the liquid post, and letting it squirt out the gas, which I pull off once I've submeged the lid as much as possible and am holding it now in the sealed position, by the bail until it seals and the running star san stops flowing.
With bare disconnects attached to the posts and the PRV turned opened with both sides of the lid completely immersed, it seems to me that would be the best assurance of getting all the air out.

 

[doug293cz]

I'll say right now that I have believed in a few myths myself and just had one of my own superstitions busted in another thread, but for me, half the point of these discussions is so I can learn better...

You are welcome.

Well sure, but that's a bit different than saying it's a complete myth that you can purge a keg with gas. People have posted charts showing O2 ppb after x purging cycles at y psi on this very forum.

...(I've searched for it but can't find it )

Here are the chart and table. I am the source of this analysis. Here's a link to the first time I posted a version of this analysis in Jan '16

Brew on

 

[mac_1103]

Any chance you might give it a try yourself? I'd love to know how many kegs could be fully submerged at once.

I don't own enough kegs to do the experiment. Also, my barrels are tapered which adds another constraint.

 

[mac_1103]

It's still not the very long O2 purging thread I'm looking for, but it does contain all the background information that my damaged brain has a hard time retaining.

ctrl+D

 

[Bassman2003]

Damn! I wish I had pictures of my process, but it takes two hands. Even tilted, because of the bale, I can't get the air out from that last maybe 1/4" side of the lid that remains above the mouth of the keg. That's why I would like to have the entire keg submerged deep enough that I can submerse the lid upside down and then flip it and insert into the corny-mouth completely under the Star San. ....Just to cover all the bases: My current process includes having a bare disconnect on the gas post while filling through the liquid post, and letting it squirt out the gas, which I pull off once I've submeged the lid as much as possible and am holding it now in the sealed position, by the bail until it seals and the running star san stops flowing.
With bare disconnects attached to the posts and the PRV turned opened with both sides of the lid completely immersed, it seems to me that would be the best assurance of getting all the air out.

The way I did it was in reverse - keg sits upright, fill with the lid closed tight but PRV open. Once liquid shoots out the PRV I close it and add a bare disconnect on the gas-out. The liquid then starts to come out the disconnect. While it is coming out I tilt the keg towards the liquid-in post. You will then see the liquid stop coming out for a bit (assuming that is the air pocket). I then take the disconnect off while the liquid is still coming out and it is finished.

 

[Broken Crow]

You are welcome.


Here are the chart and table. I am the source of this analysis.

View attachment 818510View attachment 818511

Brew on

Thank You!! You are my first-call Authority on here for math and electrical matters. I don't want to sound unapprciative or lazy, but; embarassing as this is, the part of my brain that comprhends and processes both the language and abstractions of numbers, volumes, measures, and 3D cognitive modelling, as well as the size of data-sets I can process was quite literally ripped away in 2014. (I can even trust myself to accurately count to 100 now and I used to be a maths ace )... About what percentage of a 5 or 10 lb CO2 cylinder is consumed using the 'pull the PRV x-many times' method that has been stated above?
..Like I said; this is embarassing because I can see it's just simple math, but despite my best efforts, my brain gets swamped trying to calculate it. (and I'm worried I may just be going on assumptions, but I can't be sure because connections to my insular gyrus are ripped up as well )

 

[Broken Crow]

The way I did it was in reverse - keg sits upright, fill with the lid closed tight but PRV open. Once liquid shoots out the PRV I close it and add a bare disconnect on the gas-out. The liquid then starts to come out the disconnect. While it is coming out I tilt the keg towards the liquid-in post. You will then see the liquid stop coming out for a bit (assuming that is the air pocket). I then take the disconnect off while the liquid is still coming out and it is finished.

Hmmm... OK, got it! I'm still not certain as to which way would leave more air inside.... doesn't the gas dip tube extend below the top of the keg? ...I'm gonna have to open my kegs now and look.

 

[Bassman2003]

Yes it does unless you trim it which is important for liquid purging.

 

[doug293cz]

Thank You!! You are my first-call Authority on here for math and electrical matters. I don't want to sound unapprciative or lazy, but; embarassing as this is, the part of my brain that comprhends and processes both the language and abstractions of numbers, volumes, measures, and 3D cognitive modelling, as well as the size of data-sets I can process was quite literally ripped away in 2014. (I can even trust myself to accurately count to 100 now and I used to be a maths ace )... About what percentage of a 5 or 10 lb CO2 cylinder is consumed using the 'pull the PRV x-many times' method that has been stated above?
..Like I said; this is embarassing because I can see it's just simple math, but despite my best efforts, my brain gets swamped trying to calculate it. (and I'm worried I may just be going on assumptions, but I can't be sure because connections to my insular gyrus are ripped up as well )

Sorry that you have to deal with cognitive challenges.

The amount of CO2 used will depend on the headspace volume. A ball lock corny keg has about 20.1 L total volume. 5 gal is about 19 L, so if you have a full keg the headspace is about 1.1 L. So, the volume to be purged can be anywhere between 1.1 L and 20.1 L.

If purging at 30 psig, each purge cycle uses 30 / 14.7 = 2.04 "volumes" of CO2. 1 volume of CO2 is equivalent to 1.977 g/L, so the total CO2 to purge is:

Purge CO2 (g) = Headspace vol (L) * Number of Purges * 2.04 * 1.977 g/L​

​

13 purges of a "full" keg @ 30 psig would use:

Purge CO2 = 1.1 L * 13 * 2.04 * 1.977 g/L = 57.7 g or 0.127 lb​

​

13 purges of an empty keg @ 30 psig would use:

Purge CO2 = 20.1 L * 13 * 2.04 * 1.977 g/L = 1.05 kg or 2.32lb​

​

That empty keg purge takes almost 1/2 of a 5 lb CO2 cylinder to accomplish. You don't want to use this method on anything but (almost) full kegs.

Brew on

 

[Broken Crow]

Thank You again!!! I don't want to derail this thread, but I'm nearly in tears because you laid it out so simple I can understand it! Math and comparative models used to come natural to me and half the reason I chose homebrewing as a therapy was my previously long-held belief in 'guided neuroplasticity'..that is: do the sort of things you did before the ripped axons in order to regrow, if not the original neural-net, at least re-engage the appropriate gyrii to establish functional new pathways. Even as late as 2 or 3 years ago when it came to something as simple as making coffee and pouring a mug for my girlfriend and one for myself, I'd fill one about 2/3 and the other right up to the rim and I saw them as being 'the same' even though I could plainly see that they were in some way 'different'...I had to study them to try and figure out which one was fuller....and that's without considering the horrible measurements I used in making the coffee (which I had a previous repution for doing Perfectly for 40 years, but...)
Back to the CO2 consumption; Thanks! That's far less than I thought..but still, I'd rather fill all the space with Star San (which itself probably contains dissolved O2)... I'll probably try the full submersion at some point, but now you've given me the peace of mind on a practice I can use in a pinch, and in the meantime I'll try and use the math you provided in concert with letting CO2 in my liquid post to maximize bubbles while purging to get some idea of the remaining O2.

 

[mac_1103]

The amount of CO2 used will depend on the headspace volume. A ball lock corny keg has about 20.1 L total volume. 5 gal is about 19 L, so if you have a full keg the headspace is about 1.1 L. So, the volume to be purged can be anywhere between 1.1 L and 20.1 L.

If purging at 30 psig, each purge cycle uses 30 / 14.7 = 2.04 "volumes" of CO2. 1 volume of CO2 is equivalent to 1.977 g/L, so the total CO2 to purge is:

Purge CO2 (g) = Headspace vol (L) * Number of Purges * 2.04 * 1.977 g/L13 purges of a "full" keg @ 30 psig would use:

Purge CO2 = 1.1 L * 13 * 2.04 * 1.977 g/L = 57.7 g or 0.127 lb13 purges of an empty keg @ 30 psig would use:

Purge CO2 = 20.1 L * 13 * 2.04 * 1.977 g/L = 1.05 kg or 2.32lbThat empty keg purge takes almost 1/2 of a 5 lb CO2 cylinder to accomplish. You don't want to use this method on anything but (almost) full kegs.

This definitely deserves a Ctrl+D!

 

[TLaffey]

That's far less than I thought..but still, I'd rather fill all the space with Star San (which itself probably contains dissolved O2)...

Yes, and also chlorine/chloramine. I add SMB when filling to remove both.

 

[Spivey24]

Yes, and also chlorine/chloramine. I add SMB when filling to remove both.

Why does it contain chlorine? Just because of the water used to make the star San?

 

[An Ankoù]

I use a Brewtools inline filter when kegging.

Why are you filtering a cloudy IPA?
Do you know what you're filtering out?
Quite possibly the hop oils that carry the flavour.

 

[Spivey24]

So what if there is a little O2 left in the purged keg or lines? Does it really matter? Say a small volume of air at 20% O2 diluted by 5 gallons of CO2 puts you in the parts per thousands or ten thousands. Then you go to transfer, and the beer pours into the keg pushing out all of that CO2 and O2. As the beer pours in, the gas mix swirls around in the keg and some O2 molecules hit the surface of the beer that is coming in. How much of that O2 then gets absorbed by the beer in the time it takes to fill? Say 10 minutes or so. In my brain it seems like a very tiny amount.

And further to this point, I know I get O2 in when dryhopping and that O2 will sit there for a week. Yet I take a sample from the fermenter before transferring and it’s amazing. Yet transfer to keg in a closed loop purging everything and it’s gone in a couple of days. Something more has to be going on.

 

[day_trippr]

When I read the above I see accumulating damage with an unsurprising outcome...

Cheers!

 

[Red over White]

With as close to perfect closed xfer from a pressurized fermenter as I can do into a fully fermentation purged keg, I notice a decline. Is it the headspace during the xfer and also the headspace in the keg as it's consumed? I think there may be something to the headspace having an impact, but it is only a theory.

 

[day_trippr]

For a start, always CO2-purge transfer hoses, and avoid pushing fermentor headspace gas into a keg unless the fermentor was never opened post-pitch...

Cheers!

 

[Spivey24]

I am starting to wonder if O2 mixed in with the bottled CO2 is part of the culprit. I wonder if I could test by bottling a beer at time of kegging in a purged and primed bottle and compare.

 

[CascadesBrewer]

Yes, and also chlorine/chloramine. I add SMB when filling to remove both.

How much SMB do you add? I know that The Home Brew Network has a video on his YouTube channel where he purges his kegs with Water + Metabisulfite instead of StarSan. I have been tempted to try that.

 

[TLaffey]

Why does it contain chlorine? Just because of the water used to make the star San?

Yes, I was assuming use of tap water, not RO. If you use municipal tap water for your Starsan solution, there's going to be chlorine/chloramine in there.

 

[TLaffey]

How much SMB do you add? I know that The Home Brew Network has a video on his YouTube channel where he purges his kegs with Water + Metabisulfite instead of StarSan. I have been tempted to try that.

Thanks for that reference; I may want to try that also. This is the thread that got me started on this:
Adding Sodium Metabisulphite to Keg to reduce oxygen.

I currently add 2gm SMB to 6G of starsan, which I believe to be overkill. I push out every little bit of solution before introducing beer. (I have shortened my gas tube and invert the keg to remove the last bit of solution as a final step in purging.)

 

[Bassman2003]

I am starting to wonder if O2 mixed in with the bottled CO2 is part of the culprit. I wonder if I could test by bottling a beer at time of kegging in a purged and primed bottle and compare.

This is a definite problem. The best defense is to use as little bottled CO2 as possible or buy research grade CO2 which is hard to find and probably cost prohibitive. As I posted earlier in the thread - the O2 game is difficult. All we can do it try to find ways to minimize the effects. But the first step is realizing/admitting that these seemingly tiny things throughout the process have a negative impact.

 

[mac_1103]

I am starting to wonder if O2 mixed in with the bottled CO2 is part of the culprit.

There are threads on this topic. For example.

 

[user 338926]

If it were in any way practical, I'd get myself a tank that I could submerge my entire corny in, tall enough that I could turn the lid upside-down and get that last tiny bubble out before clamping the lid down...as it is, I routinely use nearly six gallons of Star San, as I let it run out the top while I submerge as much of the lid as possible and just plain hope the the CO2 filled Star San bubbles I follow it with are enough to get that last bit of air to the PRV.

There is one practical way. It might require two kegs or at least one keg and something else you can pressurize with sanitizer in it and connect it as a sanitizer source.

Make a jumper hose with a gas fitting and if you are using another keg let's say, then you also need a beverage fitting on the other end. Now you need another beverage fitting preferably with a piece of hose on it long enough to get above the top of your keg you're trying to purge. That length is so it doesn't become a siphon or allow air back in.

Fill your keg with sanitizer. Stick the lid on. Now turn it upside down and connect your jumper hose from the liquid out of the source vessel to the gas in on your beer keg. Once you put pressure on the supply vessel, connect the other beverage line to your now upside down beer keg on the beverage fitting. The only air that can remain is what is not Disturbed and sent out by the liquid which is leaving through the beverage dip tube. I would guess that even the tiniest bit of pressure will create enough turbulence around the dip tube to remove the last tablespoon of air that could possibly be in that tank. There you go now fill it with CO2.

 

[OzzyPeeps]

If it were in any way practical, I'd get myself a tank that I could submerge my entire corny in, tall enough that I could turn the lid upside-down and get that last tiny bubble out before clamping the lid down...as it is, I routinely use nearly six gallons of Star San, as I let it run out the top while I submerge as much of the lid as possible and just plain hope the the CO2 filled Star San bubbles I follow it with are enough to get that last bit of air to the PRV.

But starsan has dissolved O2 in it and there's always a bit left in the keg ... how many people who use this method aren't bothering to dose their starsan with SMB

Better yet use saniclean to eliminate foaming residue l

I am not sure how long your cycles are and how much CO2 gets moved per cycle. But the overall point is that a sanitizer purge with CO2 or a fermentation purge are the best options. It is kind of a quest to get the dogma of pulling the PRV out of the homebrew world. It is just not the best approach and it was taught as the only approach for a long time...

Clearly the best method is a combination of best processes - i.e. sulphited liquid purge with fermentation gas.


There is one scenario I've been thinking of that would benefit from a 30x 30psi vent purge:

O2 free dry hopping in keg:

1)Fill keg with sulphited sanitizer up to about 85% full.

2)Using neodymium magnets, ss nuts and a nylon mesh, suspend the open mesh like a trampoline above the liquid and add(Frozen) hop charge so it's suspended above liquid by mesh

3) pop lid on and purge the 1 quart/ 1 liter headspace 33x at 40psi.

4) purge the rest of the liquid with ferm gas.

5) push some beer (or deoxygenated water) down the liquid out tube and then back up the same tube to clean out residuals Sani like @Red over White does

6) remove magnets to drop hops and closed loop transfer from fermenter to rack onto hops

7) pressurise to seal

8) lie keg on side on floor and kick/roll it around for 4 or 5 days at room temp

9) serve

Tasty!