How quickly does beer absorb oxygen?

Difficult question to answer with certainty. While there is math to support a solution the variables are significant depending on your technique.

When you open your fermenter the headspace should be 100% CO2 . . . but this will start to diffuse with the air (oxygen) immediately. Will it penetrate the headspace gas and reach the precious elixir? Probably, but if you leave some of the beer behind (what would be the top layer) you are reducing the problem. How much you ask? That's the part that's difficult to measure. But oxygen contamination can be minimized with good technique doing an open transfer. I'm drinking from a keg a 2 year old lager (open transferred) that is free from any dreaded oxygen that just did very well in competition.

More important is eliminating oxygen from the keg pre-transfer. Different techniques here . . . you can fill/empty with water, or let CO2 from primary purge the keg. Lots of threads discuss these methods if you search around. Once keg is oxygen free, filling from the bottom with lid attached and PRV open is a proven technique. Also, burbing the headspace, while recommended, never completely eliminates all the O2.

 

@KPlen, does your fermenter have a spigot? If so, you could conduct a closed transfer:

https://www.morebeer.com/articles/Closed_Transfer_Kegging

Cheers!

 

That is how I read it and it shouldn't take long to make the connection.

I would make the same assumption as you.

The time it should take to make the connection should be seconds. Minimal to no oxygen ingress risk here IMO.

If you can conduct this procedure, give it a go and report back.

Cheers!

 

There are various ways to prevent oxygen exposure. A CO2 "blanket" isn't really a very good one. Here's a visual demonstration of why not. It uses Br2 and NO2, both of which are even heavier than CO2.

 

To add to what Vikeman just posted:

From the linked article: The CO2 is heavier than air, so as you add it to the keg it will sink to the bottom, pushing air out through the top.

This is not true. Yes, CO2 is heavier than air but will not sink to the bottom. The two gases will mix (diffuse) and given enough time will be mixed evenly. I would not rely on this method to eliminate the oxygen from the keg.

If you don't have a tube of Bromine setting around just walk down the steps of your basement. Did you gasp for oxygen in the first 79% of the steps and only reached the heavier blanket of O2 in the bottom 21% of the basement? Pretty sure you didn't . . . the heavier oxygen (16g/mol) is equally present at the top, same as the lighter nitrogen (14g/mol) at the bottom. This is Kinetic Molecular Theory in action and some homebrewers struggle with it . . . but it's the Law.

 

Also referencing the article:
Not sure how much it would help, but before you "Pull the airlock or blow-off tube out and spray the end of the gas tubing with sanitizer before inserting into the lid...." you could reserve a bit of CO2 in the keg and use it to purge what little air might be in the tube that goes into the fermentor lid.

 

A nice find.

The so called CO2 blanket is believed by many a homebrewer. Why?
1. CO2 can pool in a low space if there is a local source, and this can be fatal. There are rules for confined spaces and their rntry in industrial settings.
2. From industrial traing films I had to set through, 10% CO2 concentrations can be fatal, and will also not support combustion. Some homebrewers years back would point to a video where CO2 was openly poured into a container with a burning candle and the candle went out. This just showed there was 10% or more CO2, not that there was 0% O2.
3. Difussion can take some time but it happens, as the video shows. In the atmosphere diffusion and mixing from the wind keep the CO2 from pooling. I've been to Badwater Basin in Death Valley at 282 feet below sea lavel, and I'm hear to type this.
4. Since diffusion takes some time, CO2 fire extinguishers work. People and animals died when Lake Nyos burped a large volume of CO2.
https://en.m.wikipedia.org/wiki/Lake_Nyos

Vinnie Cilurzo gave a talk on making IPAs years back. He talked about closed transfers, and purging the recievinng vessel and the transfer hose. It is best practice, so i follow that procedure.

 

https://www.themodernbrewhouse.com/beer-serving-oxygen-ingress/

 

Screwing around with Br2 is not worth the risk. Bromine gas reacts with water. Contact will generally result in oxybromide ions in your beer (a sterilizer; bromine can be used as a pool sanitizer!). If you're not filtering out the yeast or pasteurizing, the yeast sediment will work to minimize the effects of any residual oxygen. CO2 also reacts with water/beer, but we know that the solutions we encounter are generally slightly acidic and not a health issue. Even N2 dissolved in beer can cause problems. Guinness initiallly dissolved N2 directly into bottled beer, and used an ultrasonic bath to cause the N2 to come out of solution before it was drunk. The relatively slow dissolution of N2 could result in unpleasant N2 gas formation in the stomach.

 

I personally do not keg my beers so hopefully those who keg will respond as well.

"1. "burp the keg": does this mean just release the pressure using the pressure release valve?"

That would be my understanding/interpretation.

"2. "then vent it through the keg lid": does this mean use the pressure release valve to release all or most of the 5 psi pressure in the keg?"

My understanding/interpretation is that "vent it through the keg lid" means attaching tubing from the keg (PRV?) to the fermenter so that CO2 flows out of the keg into the fermenter as the beer is transferred.

Once again, hopefully one of the BA(s) who kegs their beer will chime in here.

Cheers!

 

Good to know about bromine. I'll send mine back!

The problem with relying on residual yeast to consume oxygen is that by the time the yeast get around to respirating anything, the damage is already done. And it is irreversible. Otherwise all bottle conditioned beers would be oxygen free, and we know that's not the case.
Cheers

 

Researchers have found that Bromine is almost always present in ytuo . . . rte5 OTOH has the Good Housekeeping seal of approval.

 

I'm about to keg a beer I dry hopped and am crashing with gelatin to clear. I've recently been keg priming for natural carbonation and to get the yeast to scavenge oxygen (although doubt it's completely effective) and I've read many discussions on SMB or the Potassium version with ascorbic acid as an O2 neutralizer.

Still trying to refine my approach and still looking for other's input.

 

Take a look at this writeup and the comments section.

https://brulosophy.com/2019/09/23/c...sulfite-smb-at-packaging-exbeeriment-results/


The answer to the original poster's question may be about a week, but that depends on a myriad of factors, including amount of oxygen, yeast activity and type, etc. Also an important factor is the human taster's sensitivity to oxidation off flavor.
One thing you may like to note is that, although forced carbonation does not encourage the yeast to scavenge oxygen, it does happen quicker than natural carbing, which speaks to the crucial time element of oxidation. In other words, yeast will scavenge oxygen as it converts the priming sugar, but that often takes at least a week, which is plenty of time for oxidation to occur.

 

@KPlen was asking how long it takes for beer to "absorb" (i.e. dissolve) oxygen during exposure to the air, not how long it takes for oxidation (via redox reactions) to happen. Both are important, but very different, questions.

Regarding the question you're addressing, about how long oxidation takes, "a week" is accurate. But so is "a minute" and a "a year," etc. All of the oxygen dissolved in the beer (or in the headspace, which will ultimately be dissolved) that isn't used by active yeast will cause oxidation. It's a continous process, the rate of which is determined in large part by temperature.

 

The difference in question you pointed out is true, but of course it's a continuous process, just like fermentation, and part of a useful answer includes what's detectable or significant. Although I mentioned the OP's question, I was answering the question above my post, as you could clearly see.