Gas-pressure puzzle?

[SanPancho]

so i've got a bunch of 2L soda bottles and carbonator caps. they are notoriously leaky if you leave the gas line attached for a typical carb process. but if you just hit em with high pressure and then disconnect, they'll hold pressure forever. (assuming your bottle is decent condition, etc) i typically boost carb my kegs, but use the bottles/caps when i take a big batch, then split it up to try different dry hops, salt levels, spices, etc.

hoping someone can solve a problem for me. the max psi on carbonator caps is 40psi per OEM. i typically fill the 2L bottle about 2/3 of the way. cooler is at 35F.

so with these specs, is there a way to calculate how long it will take to get to typical 2.3-2.5vol carb level?

 

[SanPancho]

I know there's somebody out there who's good with gas law.........

 

[m1k3]

I know not a direct answer to your question but this is what I do.

Just get the full 2L bottles cold and then shake carbonate them.
(you do need a bit of headspace, to use this method... that is the only downside... but you can squeeze the bottle so there is no air when you put the carbonator cap on)

It only takes 20 seconds to shake a bottle with 30psi or so (depending on the temperature of the liquid).

Then since I only have one carbonator cap... i put the bottle in the fridge overnight and then I can replace the cap with a standard cap. If not over-carbonated I can remove the cap the next day on a cold bottle.

I have never tried the slow carb method with a 2L bottle.

Just saw this other thread and the advice is very similar:
https://www.homebrewtalk.com/showthread.php?t=574813

 

[doug293cz]

so i've got a bunch of 2L soda bottles and carbonator caps. they are notoriously leaky if you leave the gas line attached for a typical carb process. but if you just hit em with high pressure and then disconnect, they'll hold pressure forever. (assuming your bottle is decent condition, etc) i typically boost carb my kegs, but use the bottles/caps when i take a big batch, then split it up to try different dry hops, salt levels, spices, etc.

hoping someone can solve a problem for me. the max psi on carbonator caps is 40psi per OEM. i typically fill the 2L bottle about 2/3 of the way. cooler is at 35F.

so with these specs, is there a way to calculate how long it will take to get to typical 2.3-2.5vol carb level?

I'd try about 12 hrs at 30 psi (cold.) Then adjust from there.

I have some SS carb caps from Williams, and found that they are actually a better fit for liquid QD's. Just put a black QD on your CO2 line and you may be able to leave the CO2 connected without problems.

Brew on

 

[SanPancho]

I'd try about 12 hrs at 30 psi (cold.) Then adjust from there.

I have some SS carb caps from Williams, and found that they are actually a better fit for liquid QD's. Just put a black QD on your CO2 line and you may be able to leave the CO2 connected without problems.

Brew on

very INTERESTING. i've got a few of those stainless ones myself. you think its the liquid QDs that makes it better or using the SS caps? or both?

as for 12 hours, definitely not enough, at least not without shaking. but it kills the head on your beer.

the SS cap and black QD sounds intriguing.

 

[doug293cz]

very INTERESTING. i've got a few of those stainless ones myself. you think its the liquid QDs that makes it better or using the SS caps? or both?

as for 12 hours, definitely not enough, at least not without shaking. but it kills the head on your beer.

the SS cap and black QD sounds intriguing.

I've got both plastic and SS carb caps. The plastic ones seal to the gas QD's ok, but don't seal well to the PET bottles. The SS caps have a gasket/O-ring seal to the bottle so don't leak there, but gas QD's leak. The particular SS caps I have come with a short dip tube to which you can attach a length of PVC tubing, allowing them to be used for counter pressure filling. I think that's why they fit the liquid QD's better.

The time to carb will depend heavily on the area of the gas/liquid interface. If the beer level is above the straight portion of the bottle, the area will be reduced, and it will take longer to carb. My 12 hour estimate assumes the liquid level is below the curved portion at the top of the bottle. It also assumes the gas is left connected for the entire time.

Brew on

 

[SanPancho]

this is without the gas connection. if i could get the caps to not leak when connected to gas line then i'd be in business and wouldnt need to bother. at only 2/3 full the interface is at the full diameter of the bottle, just below the shoulder. i know ive got one of the SS caps with rubber oring, maybe i'll try that.

for me the bigger issue is that the caps seal to the bottle fine, but the QD being on the cap seems to always leak if its moved or jiggled just a bit. you'd literally have to lock the bottle in place and play with the gas line until you could get it on and make sure it didnt leak. which is a pain as its down at the bottom of the cooler, with a fan blowing, so you cant really hear the leak with all the fan noise. less than ideal.

 

[doug293cz]

this is without the gas connection. if i could get the caps to not leak when connected to gas line then i'd be in business and wouldnt need to bother. at only 2/3 full the interface is at the full diameter of the bottle, just below the shoulder. i know ive got one of the SS caps with rubber oring, maybe i'll try that.

for me the bigger issue is that the caps seal to the bottle fine, but the QD being on the cap seems to always leak if its moved or jiggled just a bit. you'd literally have to lock the bottle in place and play with the gas line until you could get it on and make sure it didnt leak. which is a pain as its down at the bottom of the cooler, with a fan blowing, so you cant really hear the leak with all the fan noise. less than ideal.

The liquid QD fits tighter than the gas QD, that's why it will work. I might give it a try today, if I have too much to fit in the keg I'll be filling.

Brew on

 

[SanPancho]

good to know. i'll have to pick up a spare liquid QD but eager to see if this solves the problem of the leaks while sitting on gas.

 

[day_trippr]

I have a plastic carb cap and it's useable, but not very good at what it's supposed to do.
It won't hold a reliable seal to the QD, and you can't count on sealing to the bottle, either.

Otoh, the SS model I picked up off Alibaba a couple years ago is excellent.
Tight seals at both ends and you can shake the bejeesus out of the combo without burping gas or beer...

Cheers!