Purging oxygen without CO2 tank

[Bilsch]

Good data but not accurate or even relevant when there is a pressure differential. Ferment under (even relatively low) pressure and you won't care about these data one whit. Of course, none of these numbers are large enough to make any difference to oxidation extent anyway.

Actually pressure differential (CO2 pressure or any other gas except O2) inside the container has no effect on the oxygen diffusion through the polymer. The concentration gradient or difference in the partial pressure of oxygen on the outside vs the inside of the container is the only relevant force. You could have literally a million pounds of CO2 pressure inside and it would have zero effect on the oxygen flow through the plastic. Furthermore the oxygen will continue to flow in, only limited by the oxygen permeability of the cap, until the concentration of oxygen inside is the same as on the outside. The only way to stop it is if the container is fully impermeable to oxygen such as stainless, aluminum, glass, steel etc. Even a keg is not perfect since it has o-ring seals that are more or less permeable depending on the material. Silicone is the worst, Buna-N is one of the better materials but still pervious to a small extent. Even the seal on bottle caps will pass a small amount of gasses laterally through the seal.

 

[VikeMan]

Furthermore the oxygen will continue to flow in, only limited by the oxygen permeability of the cap, until the concentration of oxygen inside is the same as on the outside.

And, of course, that equilibrium is never reached, because O2 dissolves into the beer, seeking its equilibrium between headspace and beer. And as the dissolved O2 is used in oxidative reactions, more O2 dissolves (continually seeking equilibrium), allowing more O2 into the headspace from outside.

 

[GoodTruble]

I think " not "

I think it was "unless" instead of "if."

We all know oxygenation matters. That's not the question. The question is whether the difference caused by these different caps is significant enough to make a difference any one would notice. The article gives no indication of how much oxygenation is in play relative to it's impact on the beer. Such as if the same beer was made using the four different tops, could anyone tell the difference.

 

[DuncB]

@GoodTruble
That works as well, although not sure that you want the oxygenation to be noticeable after primary or secondary ferment for a cask ale, only once you've tapped and spiled, then it should develop the oxygenation effects as you drink it quickly!

 

[Bilsch]

The question is whether the difference caused by these different caps is significant enough to make a difference any one would notice. The article gives no indication of how much oxygenation is in play relative to it's impact on the beer. Such as if the same beer was made using the four different tops, could anyone tell the difference.

Large breweries spend a LOT of money trying to keep oxygen ingress in their beer to just a few ppb at packaging. Generally these companies don't do things on a whim or for no reason and if no one noticed then surely they wouldn't bother.

 

[GoodTruble]

Large breweries spend a LOT of money trying to keep oxygen ingress in their beer to just a few ppb at packaging. Generally these companies don't do things on a whim or for no reason and if no one noticed then surely they wouldn't bother.

Sure. But the article lists traditional air locks as allowing .14-.24% oxygen in. Is .2% going to make a noticeable difference (even if large breweries aim for less)?

 

[DuncB]

I think it's all relative really. Perfection is the enemy of good.

Until I get a DO meter I'm just going to do my best with later sealed ferments and closed transfers into kegs, stay chilled and drink the beer.

Although the beer engine is a different issue.

 

[Bilsch]

I think it's all relative really. Perfection is the enemy of good.

Choosing a closure for a carboy based on oxygen permeability data or limiting the time the beer sits is hardly perfection but merely good brewing practice.

 

[Deadalus]

It is mentioned in the Test Results section on page 2...the green arrow indicates the point where the purging was stopped.

Ok missed that. That point is really time zero.

 

[bwible]

It will. But so will not shaking. i.e. the available oxygen in the headspace is the available oxygen in the headspace. Eventually, almost all of it will dissolve. Shaking does accelerate that though.

The way to keep beer fresh long term is to keep the O2 out in the first place. Which is IMO what the video really demonstrated (or at least started to). I wish he had done this in two trials... squeezing vs not squeezing and shaking vs non-shaking. Comparing not-squeezed-but-shaken to squeezed-but-not-shaken hopelessly entangled two variables.

How about shaken-not-stirred?

 

[bwible]

To this point I've avoided secondary as a rule. One of the reasons I'm asking this is because I'm looking at bulk aging some stuff. Mainly certain malty/higher abv things that benefit from some time. As stated in OP I'm not looking to increase my bottle inventory much more at the moment.

Cool so it sounds like re initiating fermentation can help with what I'm looking at, thanks!

I do this all the time. I have 3 gallons of barleywine in a 3 gallon carboy (secondary) right now that has been sitting on oak since the beginning of December. I will be bottling that soon, maybe next week.

 

[Jafinkman]

I’ve got this same question as the OP when it comes to opening the fermenter to add dry hops. Could you purge with something like a Wine Cork Pop?