Author Topic: G-mix kegging chart  (Read 4104 times)

Offline Junction26

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G-mix kegging chart
« on: November 08, 2013, 07:32:33 AM »
I was wondering since the G mix only has 30% co2, does the extra pressure that we turn our keg to keep it carbonated?
My plan is to carbonate with o2 the switch to my G mix tank.  Is their a chart some were that will tell me what psi I should keep my G-mix at?  Like the chart for Co2. Vs temp.

Offline brewfun

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Re: G-mix kegging chart
« Reply #1 on: November 08, 2013, 05:14:57 PM »
Blended gases are best used where the required dispense pressure exceeds the dissolved CO2 level. For most beers in the US, the dissolved CO2 pressure is 12 to 15 psi. Beer left at full CO2 pressures above that will gain carbonation at the top of the keg and eventually become a foamy mess.

Blended gas has a portion that does not readily dissolve in beer (typically nitrogen) and displaces CO2, thus eliminating over carbonation. Lower carbonation beers (cask types and some Stouts) benefit from blended gas because the beer can't over carbonate. They might have the equivalent of 5 or 6 PSI in dissolved CO2, but the line requires 15 PSI to dispense.

Using a nitrogen faucet is not a requirement for these lower CO2 beers, but they sure do make 'em pretty.

So, you're on the right track. Indeed you do want to carbonate with straight CO2 according to a typical carbonation chart. Then you want to dispense with the mixed gas set for whatever your kegerator needs. On the other hand, if your dispense pressure and carbonation level are even, you want to use just straight CO2 because the blended gas will make your beer go flat as the differing CO2 levels even themselves out.
« Last Edit: November 08, 2013, 05:20:22 PM by brewfun »
Beer Appreciation is the space between pints.

Offline Junction26

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Re: G-mix kegging chart
« Reply #2 on: November 10, 2013, 08:20:23 AM »
"So, you're on the right track. Indeed you do want to carbonate with straight CO2 according to a typical carbonation chart. Then you want to dispense with the mixed gas set for whatever your kegerator needs. On the other hand, if your dispense pressure and carbonation level are even, you want to use just straight CO2 because the blended gas will make your beer go flat as the differing CO2 levels even themselves out."

Thanks,
Its good to know that my stout will not over carbonate but at the same time I don't want it to go flat between uses.  They say 30 PSI is a good starting point for the stout's.  Am I supposed to adjust the PSI to the stout to keep the carbonation level were I want it like with my regular beers?  Then adjust my serving line to make the pour like I want it?  Just like with regular beers.

Offline brewfun

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Re: G-mix kegging chart
« Reply #3 on: November 10, 2013, 10:21:15 AM »
The 30 PSI number sounds like a carbonation setting. Your actual serving pressure should equal the line resistance of your kegerator.

Hopefully, I'm keeping this basic enough that it works for you. There are a lot of considerations to draft systems and using blended gasses, which are beyond the scope of your question.
Beer Appreciation is the space between pints.

Offline Junction26

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Re: G-mix kegging chart
« Reply #4 on: November 18, 2013, 11:55:08 AM »
Yah I got to check my line resistance. My CO2 has ben doing pretty good on the standard length that keg connection sales them.   
Thanks for the help,

Offline Master

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Re: G-mix kegging chart
« Reply #5 on: November 02, 2019, 05:59:14 PM »
So I kegged a Nitro Stout, and put it on 25%/75% Beer Gas at 35psi.

Partial Pressure is 8.75psi, so I should have carbed up to right about 2 volumes at 40F.

Flat as Kansas. Tastes fine. No head, no cascade. Zero carbonation. Have checked pressure with a second gauge. It's at 35.

Any ideas? Thinking of bleeding off the headspace and just putting it on straight CO2 at 12psi for a week.

Offline brewfun

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Re: G-mix kegging chart
« Reply #6 on: November 03, 2019, 09:56:00 AM »
How long has the beer been under pressure? Have you rocked it a bit to help the CO2 dissolve? The CO2 will dissolve from the headspace downward, so the CO2 in the upper level may not have made it to the dip tube.

The CO2 level for nitro beers is very low, but not flat. Pretty much 0.5 to 0.7 vols, sometimes less if there is a lot of protein or hops in the beer. Nitrogen doesn't laminate into the beer very well, but it holds the equilibrium with the head pressure.

I assume you're using a nitro faucet, of course. 
Beer Appreciation is the space between pints.

Offline Master

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Re: G-mix kegging chart
« Reply #7 on: November 03, 2019, 12:01:47 PM »
Was under mix gas pressure for 27 days. Initial couple days were 12 psi CO2. It's been a month total.

Took it off the beer mix, burped the tank, and then put on CO2. Will see. I was aiming for 1.8 Volumes or so, using the restrictor in the stout faucet to knock a lot of it out on pouring.

 

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