Do commercial brewers purge kegs of oxygen?

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Panderson1

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I was just thinking about it. I doubt they do a star san purge like us homebrewers... maybe they do? I've seen videos of cleaning them but nothing on the oxygen issue.

They have to do something, right? Shelf life of a NEIPA is terrible.
 

MMP126

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The brewery I kind of worked at cleaned, sanitized and purged all kegs for storage. When it came time to keg beer, they purged them again, and filled them.
 

CascadesBrewer

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This is what i wonder. Are they purging 50+ kegs w star san lol.
My understanding is that it is part of their cleaning and sanitization process. Most small breweries will have a machine (like this one: Keg Washer 1-Head) that cleans, sanitizes and purges a Sankey keg.

Here is a video that turned up in a search:
 

Oleson M.D.

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Any halfway decent brewery cleans/sanitizes the inside of the keg and then purges before filling. They aren't using starsan though.

We do not use Starsan. Never have. At times simple bleach has been used. Most often One Step No Rinse is used.
 

Oleson M.D.

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The bleach was a very weak solution, perhaps a few tablespoons per gallon. It is effective, and not too expensive. But you cannot let it sit long as it will corrode stainless sreel.
 

SanPancho

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the typical process is this-

purge leftovers
rinse
hot wash
rinse
sanitize

between each step is a purge of liquid. some folks use air at the beginning to purge leftovers. then go to co2/nitro for remaining steps. extra rinse or wash cycles are sometimes added based on each wash unit and its performance. some use air at the beginning since its free. maybe first step and purge. but i'd say the vast majority of folks only use co2. some use nitrogen since its cheap via n2 generators if you got one. but by the end, you're using co2 to do final purge and keep some pressure in the keg, which helps keep bad stuff out, and is a warning if you try to fill it and find no head pressure (theres a leak).
 

Bobby_M

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The main problem I can see is that during any phase of the wash process, the gas purge is going to happen when the keg is not full of liquid so there's still a chance of gas mixing. If every push has been done with CO2 throughout, there's much less chance of residual O2. A good friend of mine was looking to ship a sixtel of NEIPA via UPS to a friend's party out of state. He asked a friendly brewery to run it through their keg washer. They handed it back and said "clean, sanitary, and purged". The beer arrived at the party, tapped and it was dark brown. Before you think anything else, the guy who filled the keg is one of the most anal brewers I know of and he never gets O2 into his process when using corny kegs. What it showed us is that at least that brewery is not getting a 100% purge on their keg washer.
 

SanPancho

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thats dependent on the brewer to do QA on their keg washing from time to time. as i already stated, some folks will go cheap and use air, but ive never seen it beyond the initial purge and maybe first rinse. this is theoretically the result.

the other likely culprit is seeing that keg go to an off sale retailer like bevmo, or liquor stores. the average joe sixpack isnt going to rent a co2 tank for the keg at his house party. just a regular pump which is pushing air.

so a kicked keg is now basically ~20% oxygen. in theory, 100% co2 purging via keg washer should be able to get that down to negligible, but it'd require full 35 to 40psi purges at each step....which isnt how they operate. only the last purge goes up to final head pressure.

a smaller self-distributing brewery with QR codes and tracking ability on their fleet should be able to catch that, herding those kegs to the "extra care" box. but any brewery that sells via distributors would require tracking from them to be passed back to the brewery on each keg. i dont think that's happening in any way at present.

the last resort is just to bay big bucks for a super fancy keg washer/filler unit that actually monitors DO levels. which might be out of reach for most folks, if it exists.
 

Wayne1

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The last brewery I worked in used a two head, manual, Premier keg washer. We followed roughly the same cycles mentioned by @SanPacho. We only used CO2. We also only used an acid with detergent for washing. We did our best to keep the kegs in as pure a CO2 condition as possible. Post sanitize (with Sani-Clean) we would purge 3 times with CO2. Fill to 5 PSA, purge, fill to 10 PSI, purge, fill to 15 psi, purge and then fill to 15 PSI again and put the keg away.
 

superiorsat

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How long would @SanPancho and/or @Wayne1 feel comfortable leaving cleaned/sanitized/purged kegs at room temp or in the walk in cooler in the brewery before filling? I don't know if I'm just a freak but I want to have freshly sanitized kegs relatively close to filling times probably under 24 hours.
 

SanPancho

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assuming your QA on your keg washer is recent and up to spec then they can sit there indefinitely. you've got an anaerobic environment under high pressure, and as long as your alkaline was low enough pH and high enough temp, and your sanitizer was high pH you've killed pretty much anything you need to worry about.

now when we've found a keg sitting in the back with a black cap on it (black=ready to use) but cant recall how long its been there or maybe even where the hell it came from, then we'd probably just put it with the dirty ones. but if i knew it was only a month or two i wouldnt think twice about using it. (assuming our keg washer QA was always good)
 

Wayne1

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As @SanPancho states, the kegs are in a CO2 environment and in a acid state. There is not much to be concerned with. To make sure we did get rid of all soils, we would periodically check the final rinse water out stream with our ATP meter. we would also, randomly pull a spear and also check it with the ATP meter.
 

k-daddy

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The last brewery I worked in used a two head, manual, Premier keg washer. We followed roughly the same cycles mentioned by @SanPacho. We only used CO2. We also only used an acid with detergent for washing. We did our best to keep the kegs in as pure a CO2 condition as possible. Post sanitize (with Sani-Clean) we would purge 3 times with CO2. Fill to 5 PSA, purge, fill to 10 PSI, purge, fill to 15 psi, purge and then fill to 15 PSI again and put the keg away.
On the purge at each psi, do you pressurize and remove gas fitting, then release the keg pressure until no more gas escapes? Also, do you wait at all for any separation of gases before the subsequent purges?
 

Wayne1

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We used Sanke kegs. There is a pressure gauge on the keg washer. We would wait until the gauge read zero. Once the keg coupler is engaged, it stays in place through out the entire process.
 

Bassman2003

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I have been learning a lot over the past few years about Co2, Oxygen and general behavior of gases. It is complex stuff. The homebrew myths around gases are mainly based upon convenience and I am sure these extend up into commercial breweries. You can not replace a liquid purge of a closed vessel unless you move a ton (slang term) of gas through that vessel - i.e. fermentation purge. Just pushing some Co2 in and burping it back out does not cut it in comparison.

This is where homebrewers can have an advantage over larger operations - we only have to deal with one, maybe two vessels at a time. So we can use a liquid purge or set up a fermentation purge and truly get all of the oxygen out which is critical for cold storage.
 

k-daddy

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I have been learning a lot over the past few years about Co2, Oxygen and general behavior of gases. It is complex stuff. The homebrew myths around gases are mainly based upon convenience and I am sure these extend up into commercial breweries. You can not replace a liquid purge of a closed vessel unless you move a ton (slang term) of gas through that vessel - i.e. fermentation purge. Just pushing some Co2 in and burping it back out does not cut it in comparison.

This is where homebrewers can have an advantage over larger operations - we only have to deal with one, maybe two vessels at a time. So we can use a liquid purge or set up a fermentation purge and truly get all of the oxygen out which is critical for cold storage.
I been utilizing fermentation gas to purge the (empty) keg. Do you think it would be significantly more effective to wait some time after the start of fermentation (to purge as much O2 as possible from the fermenter headspace) and then connect it to a liquid filed keg? Curious to know if that would make a noticeable difference in the final product.
 

Bassman2003

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No. The amount of CO2 created and pushed through the keg from fermentation gas is a lot. Plenty to clear the keg. So make sure the keg is sanitized and closed up before fermentation, run the gas through then do a closed transfer of naturally carbonated beer and you are at the pinnacle of homebrew cold side capabilities.
 
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k-daddy

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No. The amount of CO2 created and pushed through the keg from fermentation gas is a lot. Plenty to clear the keg. So make sure the keg is sanitized and closed up before fermentation then do a closed transfer of naturally carbonated beer and you are at the pinnacle of homebrew cold side capabilities.
That’s exactly what I’ve been doing. Was never sure I was getting a mostly purged keg without filling with Starsan first. Thanks.
 

doug293cz

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I been utilizing fermentation gas to purge the (empty) keg. Do you think it would be significantly more effective to wait some time after the start of fermentation (to purge as much O2 as possible from the fermenter headspace) and then connect it to a liquid filed keg? Curious to know if that would make a noticeable difference in the final product.
No, as @Bassman2003 said, the amount of fermentation gas is quite large. The case of starting with air in the fermenter headspace and keg has been analyzed. The analysis was done for worst case, and someone with an O2 meter that can read single digit ppb levels has verified that the real world results are even better than the analysis estimated (behind a paywall.)

Brew on :mug:
 

Wayne1

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A Sanke keg is a closed system. When in comes back to be cleaned, it is filled with pure CO2. The keg was fully filled with beer and then the normal serving process "purged" the beer out and left the keg filled with CO2.

The keg is then cleaned while maintaining a pure CO atmosphere. The final triple purge is to fully remove any sanitizer that may be in the keg.
 

DavidWood2115

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A Sanke keg is a closed system. When in comes back to be cleaned, it is filled with pure CO2. The keg was fully filled with beer and then the normal serving process "purged" the beer out and left the keg filled with CO2.

The keg is then cleaned while maintaining a pure CO atmosphere. The final triple purge is to fully remove any sanitizer that may be in the keg.
The commercial keg cleaner in post #5 uses caustic, which should not be used in a (sealed) CO2 environment because caustic and CO2 react and can cause a vacuum (Not to mention reduced cleaning efficacy). Here is an interesting link that shows what can happen: Caustic and CO2 reaction.
 

Nate R

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@Bobby_M ...
He asked a friendly brewery to run it through their keg washer.

when using corny kegs
Clarify- for the commercial brewer, i would assume they are using sanke 1/6, 1/4, or 1/2 barrell.
For the home brewer using corny kegs... perhaps that was the issue? Using a sanke system on a corny keg? Or did the friend use sanke corny kegs?
Just curious. I rarely, if ever, see any corny kegs in the CA breweries. In fact i wonder if it is some sort of health code or just convenice.
 

Bobby_M

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@Bobby_M ...



Clarify- for the commercial brewer, i would assume they are using sanke 1/6, 1/4, or 1/2 barrell.
For the home brewer using corny kegs... perhaps that was the issue? Using a sanke system on a corny keg? Or did the friend use sanke corny kegs?
Just curious. I rarely, if ever, see any corny kegs in the CA breweries. In fact i wonder if it is some sort of health code or just convenice.
No, you're reading into it too much. The homebrewer normally uses corny kegs and is meticulous with closed transfers. He need to ship a keg and opted to ship a Sanke Sixtel because it's more robust for shipping. When I use the term sixtel, I mean Sanke. I don't call 5 gallon corny kegs sixtels, which is possibly the source of confusion.
 

Nate R

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No, you're reading into it too much. The homebrewer normally uses corny kegs and is meticulous with closed transfers. He need to ship a keg and opted to ship a Sanke Sixtel because it's more robust for shipping. When I use the term sixtel, I mean Sanke. I don't call 5 gallon corny kegs sixtels, which is possibly the source of confusion.
Got it. I re-read your post and missed the "sixtel" completly. Got it now.
I guess my real question should have been... how does one ship a sixtel, and how much was that? Lol. Bummer the beer was skunked after all that work and money.
 

Brewer Mike

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A Sanke keg is a closed system. When in comes back to be cleaned, it is filled with pure CO2. The keg was fully filled with beer and then the normal serving process "purged" the beer out and left the keg filled with CO2.

The keg is then cleaned while maintaining a pure CO atmosphere. The final triple purge is to fully remove any sanitizer that may be in the keg.
What if the Sanke was used at a picnic with one of those hand pumps? The empty is now filled with regular air. How do you purge that air? Just by the volume of co2?
 

Wayne1

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I never had to deal with that problem as we never sold kegs for retail.

If I knew a keg had been used with air, I would rinse it, fill it with water, and then run it through the keg washer.
 

ScrewyBrewer

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According to Box Office Brewery, in Strasburg, VA., they use an automated keg washer with a controller that measures Co2 levels during the cleaning cycle—eliminating the need to fill the cleaned kegs with SaniClean while purging O2 from them before filling.
boxoffice-1.jpg
 
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doug293cz

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According to Box Office Brewery, in Strasburg, VA., they use an automated keg washer with a controller that measures Co2 levels during the cleaning cycle—eliminating the need to fill the cleaned kegs with SaniClean while purging O2 from them before filling.
View attachment 777783
I don't think that would be very effective. You really need to monitor the O2 levels, as that is the contaminant that you are trying to get/keep out of the kegs. 99.9% CO2, is still ~200 ppm O2 (assuming whatever isn't CO2 is air.) You can't measure ppb levels of O2 by trying to subtract the CO2 % from 100%.

Brew on :mug:
 

AlexKay

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I don't think that would be very effective. You really need to monitor the O2 levels, as that is the contaminant that you are trying to get/keep out of the kegs. 99.9% CO2, is still ~200 ppm O2 (assuming whatever isn't CO2 is air.) You can't measure ppb levels of O2 by trying to subtract the CO2 % from 100%.

Brew on :mug:
Beer in equilibrium with 99.9% CO2 / 0.1% air has ~9 ppb O2 in solution.
 

doug293cz

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Beer in equilibrium with 99.9% CO2 / 0.1% air has ~9 ppb O2 in solution.
Is the O2 ever really in equilibrium, or does it react with components in the beer, thus reducing the local, instantaneous concentration, and allowing more O2 to dissolve into the beer? One of the parameters commercial brewers measure is Total Packaged Oxygen (TPO.) The TPO tells you how much O2 is in the package, and that's the limit of what can eventually react with the beer.

Brew on :mug:
 

AlexKay

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Is the O2 ever really in equilibrium, or does it react with components in the beer, thus reducing the local, instantaneous concentration, and allowing more O2 to dissolve into the beer? One of the parameters commercial brewers measure is Total Packaged Oxygen (TPO.) The TPO tells you how much O2 is in the package, and that's the limit of what can eventually react with the beer.

Brew on :mug:
Depends on the headspace volume, of course. I don't know off the top of my head how much headspace is typical in a 15-gallon keg. Call it half a gallon, and 0.1% air where the oxygen totally dissolves in water gives you (order of magnitude, and if my math is correct) an additional ~7 ppb of DO.
 
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