Oxygen "Absorbing" Caps

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Pelikan

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I was looking at the Sierra Nevada site not too long ago, and they began talking about a type of beer cap that provided an oxygen barrier. They said that the plastic liner in this cap was harder than the standard bottle cap, and thus prevented oxygen from getting it (but, of course, didn't "absorb" the oxygen that was in the headspace).

So this got me thinking. I'm not 100% on this -- and anyone feel free to correct me if I'm wrong -- but I believe oxygen "absorbing" caps don't actually absorb oxygen, but do a better job of preventing it from leaking in. The plastic lining of the cap is harder and more impervious to oxygen transfer. Kinda like a bucket (standard cap) vs. a better bottle (oxygen absorbing cap). Indeed, Austin Homebrew advertises their caps as "oxygen barrier," not "oxygen absorbing." They appear to be the same silver cap advertised everywhere else as "oxygen absorbing."

Any thoughts?
 
I have wondered about this also. I heard that they are activated when they get wet, but that doesn't make sense, because they have to get wet to be sanitized. So unless you sanitize each cap individually immediatley before placing on the bottle, oxygen absorbing would have already happened probably.

AHS says they help in long term storage, so I think oxygen barrier makes more sense than oxygen absorbing. They barely cost more so I use them, but don't really know how they work.
 
There is a compound under the gas permeable liner that does absorb oxygen. Its activated when it gets wet. Therefore you can not boil or soak these caps before using. Some home brewers, myself included do not sanitize the caps before putting them on the bottle. Several of the major beer makers, Coors for one, do not sanitize the caps either.

They really do absorb the oxygen in the neck. its not just a barrier to prevent O2 from getting in.

U.S. Pat. No. 5,143,763, issued to Yamada et al., discloses a multi-layer
composition adapted to be attached to a liner on the underside of a
container cap. The layers of the composition include (1) an adhesive layer
that attaches the multi-layer structure to the cap liner, (2) an oxygen
absorbing layer consisting of an oxygen absorbent dispersed in a resin,
and (3) an oxygen permeable film layer covering the absorbent layer. The
oxygen permeable film layer prevents the oxygen absorbent from leaching
out from the resin into the contents of the container. The adhesive layer
is disposed between the cap liner and the oxygen absorbing layer,
completely separating the cap liner from the oxygen absorbing layer.
 
I'm definately not putting anything on top of my beer that has been sitting out without it being sanitized first. Even though they're in a bag in a cabinet, they sit around for months, and I open up and stick my hands in that bag every few weeks. No way am I not sanitizing those caps.
 
I didn't sanitize them when putting them on, so I suppose that's a good thing (although I did rub the lip of the bottles with a star-san rag whenever I over-filled and spilled a bit). I read a lot regarding the pros and cons of sanitizing caps, and figured with the beer having an alcohol content, and also the fact that I don't plan to shake the brew up (making it come in direct contact with the cap), I'd be fine. Oxygen is required by most (but not all) nasties that would thrive in a 5%+ ABV solution, so I suppose win-win.

I was a pretty big nit about sanitizing every thing else, the bottles included, so I'm going to hope for okay-ville. If I get some funky bottles out of this batch, I can pretty much conclude it was the lack of cap-sanitation.
 
I'm definately not putting anything on top of my beer that has been sitting out without it being sanitized first. Even though they're in a bag in a cabinet, they sit around for months, and I open up and stick my hands in that bag every few weeks. No way am I not sanitizing those caps.

You are doing yourself and your beer a disservice. No brewery sanitizes their caps. The alcohol in the beer will kill any contaminates. You need to cap and then invert for the oxy caps to work. If you sanitize them you lose the oxygen absobing properties.

Oxygen barrier and Oxygen absorbing caps are the same. Everyone sells the same caps from the same distributors.

Forrest
 
Well Forrest, you have caused me to question my practice of sanitizing my caps. It just seems really funky not to do it. Maybe it's the "old habits die hard" syndrome.
 
I think the idea is to purge the O2 in the neck as quickly as possible to eliminate any potential effects on the beer. Therefore you wouldn't want to wait days or weeks in hopes that enough moisture accumulated to activate the caps.
 
So I should turn the beers upside-down to activate the cap? Won't the gradual buildup of humidity in the bottle take care of that, or is inversion necessary?

If Forrest says to invert the bottles, turn them over. If it's too inconvenient, Use regular caps. I've had great luck with bulk normal caps lasting for years....just don't jostle your bottles about!
 
The only time I use the O2-absorbing caps is when it's a beer that is intended to be cellared for an extended period of time- a barleywine or RIS, for example.
 
Where are all the "no plastic is touching my brew" nuts out there to comment on this... come on....did you see that patent? plastics, oxygen absorbers, resins etc etc....where are you guys.


:)
 
You are doing yourself and your beer a disservice. No brewery sanitizes their caps. The alcohol in the beer will kill any contaminates.

Are you talking just the O2 caps or all caps? This is contrary to what I've read most everywhere including Palmer...

"2. Prepare your bottle caps. Bottle caps must be sanitized before use, and the best way is to soak them in sanitizing solution. Some brewers use flip-top (Groelsch style) bottles. The ceramic part of the flip tops can be sanitized along with the bottles. The rubber seals can be sanitized like the bottle caps."

It makes sense though and I always thought it was a little overboard to sanitize caps since the beer doesn't actually contact the cap (in my case atleast). However I don't buy the reasoning that the alcohol will kill any contaminates because if that were true then we wouldn't have to sanitize our bottles.
 
Are you talking just the O2 caps or all caps? This is contrary to what I've read most everywhere including Palmer...

"2. Prepare your bottle caps. Bottle caps must be sanitized before use, and the best way is to soak them in sanitizing solution. Some brewers use flip-top (Groelsch style) bottles. The ceramic part of the flip tops can be sanitized along with the bottles. The rubber seals can be sanitized like the bottle caps."

It makes sense though and I always thought it was a little overboard to sanitize caps since the beer doesn't actually contact the cap (in my case atleast). However I don't buy the reasoning that the alcohol will kill any contaminates because if that were true then we wouldn't have to sanitize our bottles.

+1 I sanitize my caps. Proof that beer can get infected while bottling my last batch I ran out of sanitized bottles so I took 1 bottle that was clean and rinsed but not sanitized and filled it, sure enough that 1 bottle was a gusher and all the rest weren't. It's such an easy thing to do why risk it?

As far as o2 absorbing, meh I'm sure they work but there shouldn't be a lot of o2 in the finished beer to begin with, and whatever does make it gets absorbed by the yeast. I think for long term storage they might be practical, otherwise o2 in headspace is a non issue for me.
 
You are doing yourself and your beer a disservice. No brewery sanitizes their caps. The alcohol in the beer will kill any contaminates. You need to cap and then invert for the oxy caps to work. If you sanitize them you lose the oxygen absobing properties.

Oxygen barrier and Oxygen absorbing caps are the same. Everyone sells the same caps from the same distributors.

Forrest

First time I have ever been told that sanitation is doing myself a disservice.

I have gotten an infection that I know came at bottling time, so no, the alcohol in the beer doesn't kill everything. I'm still going to sanitize my caps, because like I said, since I buy 3lb bags, they sit around open for months before all the caps get used. There is no way that at least one of those caps doesn't have a wild yeast cell hanging out on it, and that's a risk I'm not taking. I also agree with the previous statement, why do we need to sanitize our bottles if the alcohol will kill everything? I guess I'm just wasting the extra couple bucks to upgrade to the O2 caps.
 
First time I have ever been told that sanitation is doing myself a disservice.

I have gotten an infection that I know came at bottling time, so no, the alcohol in the beer doesn't kill everything. I'm still going to sanitize my caps, because like I said, since I buy 3lb bags, they sit around open for months before all the caps get used. There is no way that at least one of those caps doesn't have a wild yeast cell hanging out on it, and that's a risk I'm not taking. I also agree with the previous statement, why do we need to sanitize our bottles if the alcohol will kill everything? I guess I'm just wasting the extra couple bucks to upgrade to the O2 caps.

It's all about cell counts, me thinks. Will that one wild yeast cell have enough gusto to overcome the many yeast cells already in the brew, to the point of noticing off flavors? No. I doubt a guy in the industry like Forest would recommend using the O2 caps, then inverting the brew, if there was any chance at all of contamination.

We sanitize the bottles, again, because of cell counts. Many, many cells can collect in a bottle compared to a cap, unless you leave the cap out on your bathroom floor and kick it around for fun when you're using the pot.

All kidding aside, all the power to you if you want to sanitize the caps. Can't hurt, at any rate -- unless you're using those O2 buggers.
 
I'm definately not putting anything on top of my beer that has been sitting out without it being sanitized first. Even though they're in a bag in a cabinet, they sit around for months, and I open up and stick my hands in that bag every few weeks. No way am I not sanitizing those caps.
I've bottled thousands without pre-soaking or sanitizing. I use O2 absorbing caps.

Never an issue with infection.

Infections are over publicized.
 
It won't be a problem if you sanitize your caps. My point was don't waste extra money on O2 caps if you are going to sanitize them. Just use regular caps instead. If you sanitize the O2 caps you lose the benefit and the extra money spent on the caps.
 
Any of you guys who participate in swaps... do you bother with O2 absorbing caps? Or just regular caps for the trek across country?

I want to send some holiday cheer to California and it's a long haul from Tampa.
 
By the way, I inverted the brews about a day and a half after brewing to get the O2 thingies going (didn't find out about the inversion until reading about it here, you'd think that would be somewhere on the package)...hopefully I wasn't too late. Next time I'll invert at bottling.

I do tend to sit my brews down before drinking, sometimes for months in the case of stouts. I figure the O2 caps can't hurt, and at any rate the fairly negligible difference in cost between them and regulars seals the deal.
 
Any of you guys who participate in swaps... do you bother with O2 absorbing caps? Or just regular caps for the trek across country?

I want to send some holiday cheer to California and it's a long haul from Tampa.
O2 in beer tends to be a longer term problem. Short hauls during a swap, or beer stored for a few weeks shouldn't be a problem.

Now that said...you're never sure how much jostling a bottle will go through during shipment. Eliminating as much O2 as you can prior to shipping is probably beneficial. For me I prefer to cap with O2 absorbing caps, let the bottles sit for 48 hours or so, and then ship. This (in my mind) has given the bottles enough time to let the O2 be "absorbed" and reduced oxygenation.
 
It won't be a problem if you sanitize your caps. My point was don't waste extra money on O2 caps if you are going to sanitize them. Just use regular caps instead. If you sanitize the O2 caps you lose the benefit and the extra money spent on the caps.
If you had some of the O2 caps left open for a long time and were concerned about infection would a Pasteurization type process work? Say, put them in the oven at 150 degrees for 10 minutes or more. How would that effect the O2 absorbing properties of the cap?
 
O2 in beer tends to be a longer term problem. Short hauls during a swap, or beer stored for a few weeks shouldn't be a problem.

Now that said...you're never sure how much jostling a bottle will go through during shipment. Eliminating as much O2 as you can prior to shipping is probably beneficial. For me I prefer to cap with O2 absorbing caps, let the bottles sit for 48 hours or so, and then ship. This (in my mind) has given the bottles enough time to let the O2 be "absorbed" and reduced oxygenation.

thanks for the advice!
 
I know it's been a while since we discussed this, but James on Basic Brewing contacted the manufacturer to ask this very question to him. He said that sanitizing is absolutely no problem, because while the caps do absorb oxygen and are activated as soon as they get moist, it takes the caps several days to do their job, so a few minutes before getting crimped is OK. Seems like since this is the case, sanitizing them and letting them sit before shipping (or moving around at all really) would be the best way to go about using the caps. So BierMuncher, you're doing it the right way.
 
So I followed the directions of the Austin Home Brew person as I get my stuff from them. I bottled a barley wine yesterday around 11% alcohol and used the 02 caps with no sanitizer. I very nervous about contamination and wanted to get your thoughts about me taking the caps off and putting new sanitized ones on?
 
RDWHAHB It should be no problem. You have to keep your caps clean. Micro breweries around here do not sanitize the caps. I have never sanitized my caps in the last 20 years and have not had a problem. It certainly won't hurt. Wash your hands before you touch them.

Forrest
 
I know it's been a while since we discussed this, but James on Basic Brewing contacted the manufacturer to ask this very question to him. He said that sanitizing is absolutely no problem, because while the caps do absorb oxygen and are activated as soon as they get moist, it takes the caps several days to do their job, so a few minutes before getting crimped is OK. Seems like since this is the case, sanitizing them and letting them sit before shipping (or moving around at all really) would be the best way to go about using the caps. So BierMuncher, you're doing it the right way.

im glad to hear of someone doing their homework on this one,i use those caps and always sanitized thinking this was the right thing to do, but to hear it from the manufacturer tells me its o.k.(not just because so and so said it);)
 
Really good discussion in this thread. I was searching for this because I was listening to the recent Brewing Network Sunday Session about bottling and some of those dudes were advocating using oxy caps without sanitizing. They made the point that it is crucial to clean and sanitize bottles, but the caps come very clean and shouldn't present any contamination issues if handled properly.
 
So for the folks that HAVE to sanitize their caps...... Just have dip your caps in sanitizer right before placing them on the bottle. This way they are sanitized and activated. Problems?
 
So for the folks that HAVE to sanitize their caps...... Just have dip your caps in sanitizer right before placing them on the bottle. This way they are sanitized and activated. Problems?

As long as you are leaving enough time for the sanitizer to work before it potentially touches your beer. (~30sec-1minute for most).
 
As long as you are leaving enough time for the sanitizer to work before it potentially touches your beer. (~30sec-1minute for most).

I thought about that. If you dip it in the sanitizer, set it it on the bottle, and cap it, shouldn't the sanitizer do it's job on both the cap and the rim of the bottle even if it is immediately placed on the bottle? Providing you don't tip the bottles within 30 seconds or a minute?
 
Really good discussion in this thread. I was searching for this because I was listening to the recent Brewing Network Sunday Session about bottling and some of those dudes were advocating using oxy caps without sanitizing. They made the point that it is crucial to clean and sanitize bottles, but the caps come very clean and shouldn't present any contamination issues if handled properly.

I have no specific opinion on whether or not you should sanitize your caps, but I plated swabs from a few caps a while back. Two stayed clean, one showed mold contamination, and one showed both mold and bacteria. They ain't that clean :D

Whether or not that would impact a beer is of course a different question. I've done entire batches forgetting to sanitize bottles, carboys, tubing, and just about everything else we're supposed to sanitize and didn't have an obvious infection. Then again, I've also had a gusher or two over the years.

As others have mentioned, the O2 absorption happens over hours and days, not minutes. I clean everything else, and I'm not sure what the downside is to sanitizing caps. It just strikes me as a brewing "best practice" (to borrow science jargon).

And of course, there's a lot of middle ground between perfect sanitation and raging infection. Just because you don't get bottle bombs doesn't mean that your beer wasn't (perhaps only slightly) negatively impacted by cap-borne intruders. Then again, that doesn't mean it was, either. At the end of they day, everybody has their own sense of how much trouble quality control is worth. :mug:
 
I thought about that. If you dip it in the sanitizer, set it it on the bottle, and cap it, shouldn't the sanitizer do it's job on both the cap and the rim of the bottle even if it is immediately placed on the bottle? Providing you don't tip the bottles within 30 seconds or a minute?

My current procedure is to just place a non-O2-absorbing cap (sanitized for a long time) loosely on top of the bottle as soon as I fill it. When I'm done filling the entire batch, I then press the caps on. The theory behind this is that just loosely placing the cap on the bottle keeps stuff from coming in, while allowing CO2 coming out of solution in the bottle to push the O2 out (CO2 being heavier than O2?). So by the time I cap, it's mostly CO2 in the headspace.

Under this scenario, using O2-absorbing caps, I could wait until I fill the bottle to quickly dip the cap in the sanitizer (Star San). By the time I actually press the cap on, both the cap and the neck have had enough time for the sanitizer to act.

Anything wrong with this?
 
This seems to be the most "official" O2-absorbing thread I could find on HBT. Nice to hear the manufacturers recommendations.

Two points for posterity for this zombie thread:

* There are field reports of decreased carbonation from using these[1]. Can anyone comment?

* Funny enough, most styles meant for long aging actually benefit from o2 exposure (e.g. barleywine with the sherry notes) , or have enough melanoidan antioxidants to be fine anyway (e.g. imperial stout). The only real use-case I've heard of is in slowing the loss of hops flavors/aroma, but I still haven't seen much evidence one way or the other for this...

[1] http://www.northernbrewer.com/shop/review/product/list/id/210/category/22/
 
My current procedure is to just place a non-O2-absorbing cap (sanitized for a long time) loosely on top of the bottle as soon as I fill it. When I'm done filling the entire batch, I then press the caps on. The theory behind this is that just loosely placing the cap on the bottle keeps stuff from coming in, while allowing CO2 coming out of solution in the bottle to push the O2 out (CO2 being heavier than O2?). So by the time I cap, it's mostly CO2 in the headspace.

Under this scenario, using O2-absorbing caps, I could wait until I fill the bottle to quickly dip the cap in the sanitizer (Star San). By the time I actually press the cap on, both the cap and the neck have had enough time for the sanitizer to act.

Anything wrong with this?

Old thead, but interesting. I assume you are bottling from a keg then, since i don't think you will get too much CO2 from flat beer while your botteling.
 
I have heard recently that there are actually negative effects from using these caps but I haven't heard any real explanation why. Since they absorb it's possible that they might absorb CO2 and make the beer less carbed. Also, I am assuming that they might absorb hop aromas too? Again just brainstorming here.
 
I have heard recently that there are actually negative effects from using these caps but I haven't heard any real explanation why. Since they absorb it's possible that they might absorb CO2 and make the beer less carbed. Also, I am assuming that they might absorb hop aromas too? Again just brainstorming here.

Most probably the OXY caps contain the same, or similar, chemical (iron) as standard oxygen absorbing packets used for food preservation. These packets include some water to allow the chemical oxidation reaction (formation of rust) to take place and are sealed airtight to prevent the reaction from beginning until they are opened and the contents (iron and water) are exposed to oxygen.

Quote from patent " an oxygen absorbing layer consisting of an oxygen absorbent dispersed in a resin."

Unlike the food storage packets which also contain a small amount of water the oxy-caps use DRY iron which must first be moistened to become activated, thus they must be wet first. The reaction is also SLOW so the few minutes they spend in a sanitizer should not have any real effect on them.

The following is OMO.

They absorb OXYGEN and nothing else. As long as your bottles are stored upright the beer does not contact the absorbant layer for any length of time there should be no problems with off flavors from the cap.

bosco
 
I just want to say that thank god the alcohol doesn't kill everything because if it did, we wouldn't have bottle fermentation cuz the alcohol would kill the yeast.

Also about capping the bottles and then tipping them upside down to wet the cap to activate it, wouldn't that help the oxygen absorb into the beer helping it to oxidize quicker?

Think I'll continue my old practice of sanitizing the caps.
 
I have also wondered about the inverting since I would agree that it would let some of the 02 into the solution. I have always sanitized my caps, seems to me it's not worth the risk to not do it. I know this has been thoroughly discussed in this thread but it's just MHO.
 
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