This contraption isn't working

[p_p]

Soooooo keeping up with the co2 blanket and such, I tried capturing some CO2 by wrapping a bag around the airlock. The idea was to have a small reserve that would get sucked back in during cold crash.

It ain't working.

Despite the brew having bubbles for about two days the bag is not inflating. I am wondering if these bags are just permeable and I have achieved nothing.

Which brings me to the question, how can I capture some CO2? I need one of those balloons made out of some sort of metallic paper.

 

[GilaMinumBeer]

Foil coated mylar are the balloons.

Not sure that'll solve the issue tho.

 

[Dfitz]

Try a latex condom.

 

[TheMadKing]

Interesting idea, I would just use a rubber party balloon and a hose clamp, most plastic bags are gas permeable (balloons included, its just a matter of HOW permeable). In general, that seems like more effort than it's really worth to me.

You could also just transfer to a keg and seal it, then cold crash in a sealed airtight container. It will pull a vacuum slightly but it won't suck air.

 

[IslandLizard]

Odds are the lid isn't sealing well enough. The itty bit of restriction from the bag is probably enough to let the CO2 escape the easier way, through the rim/lid seal.

How come that bag is slightly inflated, though?

 

[Shawn3997]

Where does one get that nifty volume adhesive strip? Everything I've used to mark gallons on my carboys has come off so far.

 

[p_p]

Odds are the lid isn't sealing well enough. The itty bit of restriction from the bag is probably enough to let the CO2 escape the easier way, through the rim/lid seal.

How come that bag is slightly inflated, though?

Not really. In the bag there is a very active s-type airlock.
Maybe the bag has a big hole in it and here I am, scratching my head over why it does not inflate.

Btw, I am on my third bag, each time I find a thicker one, I change it hoping this time it will work... Oh, man. I need better equipment.

The bag inflated to that level, which was promising, and then stalled. Co2 must be scaping somehow... I was trying to figure out if this is a "property" of cheap supermarket bags

 

[p_p]

Where does one get that nifty volume adhesive strip? Everything I've used to mark gallons on my carboys has come off so far.

The trick is never to wash the bucket

 

[p_p]

Try a latex condom.

That would work, but I am dealing with a plastic bucket with a snap on lid, any significant pressure and it will start leaking. I was hoping the bag would act as a reservoir without increasing the pressure the water in the airlock sees.

 

[BeardedBrews]

Poke a hole in the bottom of a small bucket, glue your blow-off tube into the bottom of that, flush with the bottom, and then poke your S-Lock into the blow-off tube. The small bucket will fill with CO2 from the bottom up, and when you start sucking a vacuum through the S-Lock it will pull the CO2 out of your little bucket.


[Edit] If you're worried about O2 exposure in your beer you should probably think about changing your fermentation vessel. I have not bought into the LoDO camp, but I know your bucket isn't ever going to be O2-proof. Fermenting under pressure in a keg is a pretty nice option.

 

[IslandLizard]

Not really. In the bag there is a very active s-type airlock.
Maybe the bag has a big hole in it and here I am, scratching my head over why it does not inflate.

Btw, I am on my third bag, each time I find a thicker one, I change it hoping this time it will work... Oh, man. I need better equipment.

The bag inflated to that level, which was promising, and then stalled. Co2 must be scaping somehow... I was trying to figure out if this is a "property" of cheap supermarket bags

CO2 is escaping you. The thickness of the bags is not important until there's a significant pressure gradient, and even then, gas exchange is still very, very slow across a plastic bag membrane.

Bucket rims are notorious for bad seals. Unless there's a good sealing rubber gasket or o-ring inside the lid's groove, it's a toss up. I've had buckets that showed no bubbles in the airlock at all, yet the beer fermented in 5 days. Others were breathing like wild animals for 2 days (@65°F!).

 

[p_p]

Never mind... I am trying to fix a problem that is inherit to the type of equipment I am using ...

The iidea was good as I can hear CO2 flowing into the bag through the airlock which means It is not escaping through the lid.. Execution however, poor. Bag isn't inflating.

 

[IslandLizard]

Never mind... I am trying to fix a problem that is inherit to the type of equipment I am using ...

The iidea was good as I can hear CO2 flowing into the bag through the airlock which means It is not escaping through the lid.. Execution however, poor. Bag isn't inflating.

CO2 leaks out where the bag seals around the airlock?

A small leak is enough to prevent the bag from filling, since a little over-pressure is needed to make it expand (swell). Any leak in the system will prevent that. Try one of those mylar balloons, they're very light weight, and the fill hole is narrow. Maybe it will seal better, but again, any leak on the rim may still prevent it from filling.

I once had a bucket lid bulge nearly 1/2 inch from CO2 production, before it would suddenly release through the 1/2" ID blow-off tube into a jar with Starsan. Never seen it again since. I guess there was a good seal on the rim then.

 

[p_p]

CO2 leaks out where the bag seals around the airlock?

A small leak is enough to prevent the bag from filling, since a little over-pressure is needed to make it expand (swell). Any leak in the system will prevent that. Try one of those mylar balloons, they're very light weight, and the fill hole is narrow. Maybe it will seal better, but again, any leak on the rim may still prevent it from filling.

I once had a bucket lid bulge nearly 1/2 inch from CO2 production, before it would suddenly release through the 1/2" ID blow-off tube into a jar with Starsan. Never seen it again since. I guess there was a good seal on the rim then.

Actually, it is filling. I changed the bag and started using one of those thick heavy duty reusable store bags. Tied tight to the hose with some elastic bands and the seam taped.

Still, after having read the articles that Yooper posted, I am thinking that although using this bag to suck back in CO2 during cold crash will help, the bag will not have pure CO2 in it, plus my bucket lid and the interface with the bung and airlock is probably leaking anyway ...

Anyway, I learnt a lot about oxygen in this thread and some others I am participating. cheers.