How long for a specific # CO2 volumes?

[stevedasleeve]

I have a ton of information on what PSI to set for X volumes, in charts and books etc. but no time info! If I want to achieve 2.2 volumes in a regular 5 gallon corny keg at 40 F...

for how long and at what PSI do I need?

Thanks for any help!

[Kbar]

Beersmith says 9.02 Psi. As for time, I seem to have similar issues. I hold it there for weeks. My issue is that even with the appropriate length of tybing to achieve the pressure drop I need to serve and maintain the correct volumes of CO2, it pours way too fast. When I meter the tap, it foams. I am still experimenting.

[stevedasleeve]

Beersmith says 9.02 Psi. As for time, I seem to have similar issues.

Yes that's my point. I have the same charts, many sources, all say "x psi for x volumes" but none say for how long. What I'd like to know is if I force carbonate at x psi, how long will it take for the beer to be carbonated at x volumes? And after that is the CO2 amount static? If I keep the beer under say 8 psi will it absorb more CO2 or is that just the appropriate pressure to force it out the tap?

[stevedasleeve]

Beersmith says 9.02 Psi. As for time, I seem to have similar issues.

Yes that's my point. I have the same charts, many sources, all say "x psi for x volumes" but none say for how long. What I'd like to know is if I force carbonate at x psi, how long will it take for the beer to be carbonated at x volumes? And after that is the CO2 amount static? If I keep the beer under say 8 psi will it absorb more CO2 or is that just the appropriate pressure to force it out the tap?

[manwithbeers]

Applying 9 PSI at 40 degrees will get you to 2.2 Volumes of C02. Keeping the pressure at 9 PSI will keep the Carbonation at 2.2 volumes. To dispense at the right speed you need the proper length of line to balance the pressure getting to the tap. More pressure = more line. Less pressure = less line.Here are a couple links for your future reference.


http://www.angelfire.com/ks2/beer/homekeg.html

http://hbd.org/cgi-bin/recipator/recipator/carbonation.html?12181271#tag

Unless you shake the keg to speed the gas absorption the process will take 3 to 4 days at the correct pressure to properly carbonate. Increase the pressure temporarily (1 day at 20 psi?) to speed the process.

[BrewerBC]

Unless you shake the keg to speed the gas absorption the process will take 3 to 4 days at the correct pressure to properly carbonate. Increase the pressure temporarily (1 day at 20 psi?) to speed the process.

I do 20-30 for a day or two. works great.

[ajdelange]

There are lots of places to get the basic pressure setting values.

Vols = (PSIG + 14.695)*(0.01821 + 0.090115*exp( (32-T)/43.11)

or

PSIG = Vols/(0.01821 + 0.090115*exp( (32-T)/43.11) - 14.695

with the temperature in °F are hand formulas which came from a fit to the ASBC's table and are quite accurate. They don't say anything about how long pressure needs to be applied because that varies greatly depending on how well you "mix" the beer and CO2. Injecting the CO2 into the beer with a sintered "stone" can get you to a desired level of carbonation within minutes. OTOH if you dial in the pressure you want and apply it through the gas port on a full sized (15.5 gal) keg without any agitation it can take several weeks before the whole volume of beer is at close to equilibrium. Bear in mind that you draw beer from the bottom of the keg and apply the gas at the top so the part you are drawing is the last to come up to full gas pressure.

Setting the pressure to 2 to 3 times the final pressure you want will, of course, get you there faster as will shaking the keg. However you do it there is more to it than just getting the CO2 dissolved. It takes additional time for the gas to meld with the beer. I don't understand the physics here. It will be a month or more before the beer pours with the fine, meringue like head we really want.

[beltbuckle]

Beersmith says 9.02 Psi. As for time, I seem to have similar issues.

Yes that's my point. I have the same charts, many sources, all say "x psi for x volumes" but none say for how long. What I'd like to know is if I force carbonate at x psi, how long will it take for the beer to be carbonated at x volumes? And after that is the CO2 amount static? If I keep the beer under say 8 psi will it absorb more CO2 or is that just the appropriate pressure to force it out the tap?

I've never seen any scientific study on it, but from my experience, if you use the "set it and forget it" method of force carbing, it takes between one and two weeks to reach equilibrium. It's mostly there after a week.