Gouden Bier and Co2 volumes

[Sidman]

Got a special edition gouden Bier recipe from my local HBS but I can't seem to find any info on co2 volumes for keg carbonation. I have had it set at 10 psi @ 38 degrees but it seems extremely flat. Any ideas?

 

[helterscelter]

How long have you had it on the gas? Maybe need to wait a little longer?

 

[Sidman]

Two full weeks.

 

[doug293cz]

Two full weeks.

Two weeks should get you close to equilibrium carb level. More time might help a little, but likely not much.

Do you live at high elevation? If so you need to correct for atmospheric pressure by upping the CO2 pressure.

How many times did you purge the headspace with CO2 after sealing the keg? Not doing an adequate purge can reduce the effective CO2 pressure (more properly the CO2 partial pressure.)

Edit: Another question: Was the keg cold when you first applied the CO2 pressure.

If those don't apply, try upping the pressure to 12 psi, shake the keg, let it settle overnight, and see if you like that level of carbonation better.

Brew on

 

[Sidman]

I am wondering if the issue is with my distribution tap. This is the first time I have had four kegs all on the same co2. I have a 4 way dist tap and each tap has an approx. 4 to 6 foot line. I have the regulator set for 12 psi. Would I need to bump this up to account for the four cornys?

 

[Sidman]

Two weeks should get you close to equilibrium carb level. More time might help a little, but likely not much.

Do you live at high elevation? If so you need to correct for atmospheric pressure by upping the CO2 pressure.

How many times did you purge the headspace with CO2 after sealing the keg? Not doing an adequate purge can reduce the effective CO2 pressure (more properly the CO2 partial pressure.)

Edit: Another question: Was the keg cold when you first applied the CO2 pressure.

If those don't apply, try upping the pressure to 12 psi, shake the keg, let it settle overnight, and see if you like that level of carbonation better.

Brew on

I am at pretty low elevation.
I am not even sure I purged the keg after sealing. If I did it would have only been once.
I had cold crashed the beer so it was approx. 40 degrees when I put the gas on.

Thanks for the suggestions

 

[helterscelter]

I am wondering if the issue is with my distribution tap. This is the first time I have had four kegs all on the same co2. I have a 4 way dist tap and each tap has an approx. 4 to 6 foot line. I have the regulator set for 12 psi. Would I need to bump this up to account for the four cornys?

you shouldn't need to adjust pressure to account for more kegs in your distribution. did you check your keg for leaks? I suspect it would drain your co2 if it was leaking, but a slow leak in the keg would result in a lower pressure in the keg and lower carbonation levels in the beer. (just reaching here.)

 

[doug293cz]

I am at pretty low elevation.
I am not even sure I purged the keg after sealing. If I did it would have only been once.
I had cold crashed the beer so it was approx. 40 degrees when I put the gas on.

Thanks for the suggestions

I think your problem is the lack of a purge. Let's walk thru an example:

1. The regulator gauge reads pressure above atmospheric. So you start with 14.7 psia (absolute) and add 10 psi of CO2. Total pressure in the keg is 24.7 psia. The composition is 14.7/24.7 = 59.5% air and 40.5% CO2.
2. Now when you vent the keg pressure drops to 14.7 psia, but the composition is still 59.5% air & 40.5% CO2. The CO2 partial pressure is 14.7 * 0.405 = 5.9 psia
3. Now pressurize the keg with 10 psi CO2 again. The CO2 partial pressure becomes 15.9 psia. The other 8.8 psi needed to get the total 24.7 psia comes from the air

The carbonation charts assume that the gas in the keg is 100% CO2. So at 10 psig (gauge) you should have 24.7 psia of CO2 pressure. This should give 2.38 volumes @ 38°F. But as we saw above, you only have 15.9 psia of actual CO2 in your keg. To find the resulting carbonation level, we convert psia to psig by subtracting 14.7. 15.9 - 14.7 = 1.2. If we look at the chart 1.2 psig of CO2 @ 38°F only gives about 1.54 volumes of CO2. Way below your target.

You can still go back and purge the kegs more (say about 5 times) to get rid of most of the air which is causing your problems.

Brew on

 

[Sidman]

I think your problem is the lack of a purge. Let's walk thru an example:

1. The regulator gauge reads pressure above atmospheric. So you start with 14.7 psia (absolute) and add 10 psi of CO2. Total pressure in the keg is 24.7 psia. The composition is 14.7/24.7 = 59.5% air and 40.5% CO2.
2. Now when you vent the keg pressure drops to 14.7 psia, but the composition is still 59.5% air & 40.5% CO2. The CO2 partial pressure is 14.7 * 0.405 = 5.9 psia
3. Now pressurize the keg with 10 psi CO2 again. The CO2 partial pressure becomes 15.9 psia. The other 8.8 psi needed to get the total 24.7 psia comes from the air

The carbonation charts assume that the gas in the keg is 100% CO2. So at 10 psig (gauge) you should have 24.7 psia of CO2 pressure. This should give 2.38 volumes @ 38°F. But as we saw above, you only have 15.9 psia of actual CO2 in your keg. To find the resulting carbonation level, we convert psia to psig by subtracting 14.7. 15.9 - 14.7 = 1.2. If we look at the chart 1.2 psig of CO2 @ 38°F only gives about 1.54 volumes of CO2. Way below your target.

You can still go back and purge the kegs more (say about 5 times) to get rid of most of the air which is causing your problems.

Brew on

Excellent help and thank you. So after sealing how many times should I purge the keg as a standard practice?

 

[doug293cz]

Excellent help and thank you. So after sealing how many times should I purge the keg as a standard practice?

I like to purge 3 - 5 times at 30 psi. If you work thru the math above using 30 psi vs 10 psi, you'll see that you get more air out with each purge. The extra purges are more to get the O2 level down, as two purges @ 30 psi would be more than adequate just to insure proper CO2 partial pressure for carbonation.

Brew on

 

[Sidman]

I like to purge 3 - 5 times at 30 psi. If you work thru the math above using 30 psi vs 10 psi, you'll see that you get more air out with each purge. The extra purges are more to get the O2 level down, as two purges @ 30 psi would be more than adequate just to insure proper CO2 partial pressure for carbonation.



Brew on

Ok. So 3 to 5 times at 30 psi. Do you hold it there just long enough for it to fill back up? Then I assume once you have completed those purges it's down to 10 to 12 psi. How long does it take for the keg to be conditioned well enough for drinking?

 

[helterscelter]

Ok. So 3 to 5 times at 30 psi. Do you hold it there just long enough for it to fill back up? Then I assume once you have completed those purges it's down to 10 to 12 psi. How long does it take for the keg to be conditioned well enough for drinking?

Once you purge it, you put it back on at your target psi. Since you're already partially carbed it should be ready in just a couple days.

 

[doug293cz]

Ok. So 3 to 5 times at 30 psi. Do you hold it there just long enough for it to fill back up? Then I assume once you have completed those purges it's down to 10 to 12 psi. How long does it take for the keg to be conditioned well enough for drinking?

Yeah. On both the fill and vent, I wait till the sound of rushing gas stops, and then immediately vent or refill.

If you are doing "set and forget" where you just put it at serving temp and pressure and wait, it takes about two weeks to get to "drinkable" carb level. It continues to pick up some additional carb for about another week.

If you want to get it to carb quicker, you can pressurize to 30 psi and chill. Only leave the 30 psi on for 24 - 36 hours. Longer than 36 hours, and you will have to learn the joys of dealing with overcarbed kegs. After 36 hours @ 30 psi, vent the keg and reduce to serving pressure. This method will give you reasonably carbed beer in about 3 days.

Another fast carb method is to chill the beer and connect it at serving pressure. Then disconnect the QD and roll the keg around for a minute or two. Repeat the pressurize and roll sequence until you can no longer hear any gas entering the keg when you connect the QD. Then leave the gas connected and put the keg back in the cooler. It's ready to serve immediately, but may be cloudy. I have no personal experience with this method, so don't know how many iterations it typically requires.

Lastly, some people try combining the last two methods, but cut down the number of iterations to try to avoid overcarbing. This method is very difficult to control and is the most likely to result in overcarbing. I don't recommend it.

Brew on