Short-term dispensing through stout faucet with 100% CO2...?

[CplHunter]

I am having a party in a couple of weeks. I purchased a stout faucet and have researched N2/CO2 mixes and the whole beer gas subject.

As a temporary cheap-out method, I'm considering attempting to push through the faucet with CO2 only, given that it will only be on gas for approx 8 hours.

My proposed method:

1. Pressurize the keg to 30 PSI to seal the keg.
2. Disconnect keg from gas.
3. Chill keg at 39 DegF for two weeks (purely due to schedule).
4. Hope and pray that 30 PSI in the head space will settle the beer to around 1.2 volumes.
5. On day of party (and at start time of party), hook up keg to 30 PSI of CO2.
6. Hope and pray that keg does not over-carbonate during the 8 hour serving window.
7. After the serving window expires, if the keg is not kicked, disconnect gas and relieve all pressure in head space of keg.

My main concerns:

1. Will the keg over carbonate in 8 hours? If this were to occur, I would swap in a standard faucet as a backup.
2. Loss of seal on keg during two weeks at 39 DegF with no gas on the keg. Worst case here is I get a flat beer.

I can't seem to find a CO2 solubility rate chart/calculator so I have nothing to go on other than my limited experience with force carbonating. There are other threads on this subject but they do not really deal with it on the short-term. Has anyone tried this with any success?

 

[btbnl]

Serving on CO2 should be OK - normally it would take a couple of days to reach equilibrium.

If the party isn't for a for couple of weeks though I'm not sure why you're carbing like that rather than just holding it at 7-8 PSI at 39 F for the duration, or even warm-carbing at around 12 PSI (depending on ambient temperature).

 

[CplHunter]

I didn't want to put it on gas for two weeks at 39 F because according to all of the charts I have, it will over carbonate. 7 PSI at 39 F will give about 2.1 vols.

I have considered warm carb but the logistics of my home would require a second CO2 setup for that (which I might be able to make happen). The 39 F approach is just the easiest for me, but I will pursue the warm carb option as well.

 

[55x11]

I didn't want to put it on gas for two weeks at 39 F because according to all of the charts I have, it will over carbonate. 7 PSI at 39 F will give about 2.1 vols.

I have considered warm carb but the logistics of my home would require a second CO2 setup for that (which I might be able to make happen). The 39 F approach is just the easiest for me, but I will pursue the warm carb option as well.

You can raise the temperature a bit, or use lower pressure, or use sugar to carbonate the keg "naturally".

For example, can you carb it at 6psi at 65F? that's about 1.1 volumes.

I am not sure why you think 30 psi at room T and then disconnecting it and cooling it will give you 1.1 volumes. It can give you a lot more, or a lot less, depending on volume of headspace vs. beer etc.

Additionally, I would make the beer line as short as possible so perhaps you can serve at lower pressure than 30 psi and still get the desired faux-nitro effect.

The beer will begin to over-carb, but it will take longer than 8 hours to reach equilibrium for sure.

 

[CplHunter]

You can raise the temperature a bit, or use lower pressure, or use sugar to carbonate the keg "naturally".

For example, can you carb it at 6psi at 65F? that's about 1.1 volumes.

The main reason for the 30 PSI initially was to seal the keg, although now that I think about it...I could just vent that off after it is sealed. Your idea of raising the kegerator temp is a good one. At 60 F, I can obtain 1.2 in the stout and still have enough room on the top end to carbonate my hefe.

Now I have two questions:

• Can I successfully force carbonate at 60 F in two weeks, or does the increase in temperature cause this process to slow, even given the increased pressures per the carb charts?
• And on my original subject, can I push with 30 PSI of CO2 for 8 hours without serving glasses of foam after a few hours? This isn't just a question of time to equilibrium, but more of, "In 8 hours, will the vols increase to a point where foaming is an issue?"

 

[Bobby_M]

The only reason you need to pour through a stout faucet at 30+ PSI is due to the restricter plate. Just remove that and you can pour at 10psi just fine.

 

[CplHunter]

The only reason you need to pour through a stout faucet at 30+ PSI is due to the restricter plate. Just remove that and you can pour at 10psi just fine.

My intent is to get as close to a creamy nitro head as possible. I don't expect it to have a mesmerizing cascade like a Guinness, but I do plan to push through the restrictor plate.

 

[55x11]

The main reason for the 30 PSI initially was to seal the keg, although now that I think about it...I could just vent that off after it is sealed. Your idea of raising the kegerator temp is a good one. At 60 F, I can obtain 1.2 in the stout and still have enough room on the top end to carbonate my hefe.

Now I have two questions:

• Can I successfully force carbonate at 60 F in two weeks, or does the increase in temperature cause this process to slow, even given the increased pressures per the carb charts?
• And on my original subject, can I push with 30 PSI of CO2 for 8 hours without serving glasses of foam after a few hours? This isn't just a question of time to equilibrium, but more of, "In 8 hours, will the vols increase to a point where foaming is an issue?"

1. I am sorta guessing here (but using common sense and some basic science) since I usually carb at serving temperature, but sure - you should be able to carbonate at 60F in two weeks, probably even a week or faster. You are only carbing to 1.1 volumes which should be quick. Increased temperatures usually speed up diffusion process, so equilibrium should be reached sooner.

2. A lot of us "burst"-carbonate our beers, which involves applying 30psi at say 40F for about 24 hours (starting with uncarbonated beer), following 10 psi or so for another 24-48 hours. The idea is to speed up initial adsorption of CO2 by applying higher pressure, and reduce it as equilibrium is being approached - to avoid over-carbing.
This tells me that 30 psi for 24 hours doesn't quite give me 2 volumes of CO2 (in your case it will be even slower since you will already have some CO2 in the beer, so difference is more like 15-20 psi or so?).
So I would argue that 30 psi for just 8 hours may bump your 1.1 volumes to maybe 1.5-1.8 volumes or so, but won't overcarb the beer (assuming you start with 1.1 volumes)

If you are still paranoid about over-carbing, just try to disconnect the gas in line and purge the keg of extra pressure if you are not serving from it for an hour or so.

 

[CplHunter]

An update with my lessons learned:

1. Temperature appears to have bearing on the time required to carbonate, even with increased pressures according to the carbonation charts. The 2.4 volume beers were still quite flat after 8 days on CO2 at 62F and 20PSI. I had to take remedial action, decrease temps, and burst carb them to make my serving dates.
2. On pure CO2, at 40F and 30PSI, the stout poured very well (cascading effect and creamy head) for about 4 hours after pressure was applied. It then began a gradual decline until 8 hours after tapping, you were getting a full glass of foam which would eventually settle to around half a glass.

 

[day_trippr]

fwiw, according to our favorite carbonation table, 20 psi at 62°F will eventually reach equilibrium at only 2.14 volumes.

And as the https://www.homebrewtalk.com/showthread.php?t=73328]green line, shows "eventually" is roughly 2.5 weeks...

Not surprised about the outcome, properly carbing and then using a nitro faucet with actual "nitro" is tricky enough for first-timers...

Cheers!