A few technical questions about force carbing in a keg.

Question 1
If I fill 2 5g kegs with the same 10g batch of beer and put them both in my keggerator on 12psi CO2 but only hook up one keg to a tap and then take daily samples off that keg (let’s say 10oz/day in samples) after 5 days will both kegs be equally carbonated or will one have more corbonation? If different which one will be more carbed?

Question 2
If I have a 9g batch and I fill one keg with 5g and the other keg with 4g then put them both in the keggerator at 12psi will one carb up before the other one? Which one?

Question 3
If I start with uncarbed beer in a 5g keg at 40f and pressurize it to 20psi with CO2 then dissconnect the CO2 will the pressure still be at 20psi 10 days later (assuming no leaks, and temp stayed constant at 40f)?

Question 4
If I chill my keg to 33f and carb using 12psi of CO2 for 7 days, then bring the keg up to 40f will it be over carbed (if 12psi @40f would have given me perfect carb)?

Question 5
If the temp in the bottom of my keggerator is at 32f but the top of my keggerator is 45f then I assume the beer in the bottom of the keg is colder than the bear at the top of the keg. If the headspace where the CO2 is at is warmer will that cause my beer to take longer to carb than if the temp were the same throughout (so the uniform temp would be warmer than 32f but colder then 45f)?

Question 1
If I fill 2 5g kegs with the same 10g batch of beer and put them both in my keggerator on 12psi CO2 but only hook up one keg to a tap and then take daily samples off that keg (let’s say 10oz/day in samples) after 5 days will both kegs be equally carbonated or will one have more corbonation? If different which one will be more carbed? -Should be close but keep in mind different styles and FG will absorb CO2 differently

Question 2
If I have a 9g batch and I fill one keg with 5g and the other keg with 4g then put them both in the keggerator at 12psi will one carb up before the other one? Which one? Should be about the same, see above

Question 3
If I start with uncarbed beer in a 5g keg at 40f and pressurize it to 20psi with CO2 then dissconnect the CO2 will the pressure still be at 20psi 10 days later (assuming no leaks, and temp stayed constant at 40f)? The beer will continue to absorb gas, at 20PSI I would assume your will have a hard time serving since the beer will be carbed over 3 volumes and might not be style appropriate.

Question 4
If I chill my keg to 33f and carb using 12psi of CO2 for 7 days, then bring the keg up to 40f will it be over carbed (if 12psi @40f would have given me perfect carb)? I would just keep the temp at 40 and keep things simple

Question 5
If the temp in the bottom of my keggerator is at 32f but the top of my keggerator is 45f then I assume the beer in the bottom of the keg is colder than the bear at the top of the keg. If the headspace where the CO2 is at is warmer will that cause my beer to take longer to carb than if the temp were the same throughout (so the uniform temp would be warmer than 32f but colder then 45f)?[/QUOTE] I would doubt that the beer inside the keg has a 13 degree difference regardless of the air temp. I would add some more insulation though.

I add kegs to 40 degree keezer and hook it up to 12-14PSI and its ready to go in 7-10 days, I try and keep it simple with the least amount of things to do.

I am not a engineer but here is my shot at it... Though I wonder why all the questions???? I have been getting away from forced Carbonation when not in a rush... 3 to 5 oz of corn sugar depending on style has been working form me... I error to the high side so if needed I can vent some off.

Question 1
If I fill 2 5g kegs with the same 10g batch of beer and put them both in my keggerator on 12psi CO2 but only hook up one keg to a tap and then take daily samples off that keg (let’s say 10oz/day in samples) after 5 days will both kegs be equally carbonated or will one have more corbonation? If different which one will be more carbed?
If they are always on the gas for the same amount of time they should be pretty close

Question 2
If I have a 9g batch and I fill one keg with 5g and the other keg with 4g then put them both in the keggerator at 12psi will one carb up before the other one? Which one?
I would assume that the four (4) gallon keg will be more carbonated because they was more FREE CO2 in the tank to absorbe it... (less liquid and more gas)
Question 3
If I start with uncarbed beer in a 5g keg at 40f and pressurize it to 20psi with CO2 then dissconnect the CO2 will the pressure still be at 20psi 10 days later (assuming no leaks, and temp stayed constant at 40f)?
No some of the gas should be absorbed by the beer... This is how I force carbonate sometimes... coming back each day and pumping more it to the keg.
Question 4
If I chill my keg to 33f and carb using 12psi of CO2 for 7 days, then bring the keg up to 40f will it be over carbed (if 12psi @40f would have given me perfect carb)?
Maybe... but this is an easy one to fix,,, vent off your gas pour beer into a pitcher until it comes out the way you want it and then hookup the gas at the proper temp.
Question 5
If the temp in the bottom of my keggerator is at 32f but the top of my keggerator is 45f then I assume the beer in the bottom of the keg is colder than the bear at the top of the keg. If the headspace where the CO2 is at is warmer will that cause my beer to take longer to carb than if the temp were the same throughout (so the uniform temp would be warmer than 32f but colder then 45f)?
Scooby???? That is a hell of a temprture change (is this thing on ICE?)... but beer is a liquid I would assume a little convection/mixing just from serving... I have put Corney Kegs in ice only a third of the way up and never have had a problem.

Gameface said:

Question 5
If the temp in the bottom of my keggerator is at 32f but the top of my keggerator is 45f then I assume the beer in the bottom of the keg is colder than the bear at the top of the keg. If the headspace where the CO2 is at is warmer will that cause my beer to take longer to carb than if the temp were the same throughout (so the uniform temp would be warmer than 32f but colder then 45f)?

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The beer will be at a constant temp throughout. Liquid will conduct that temperature rather well (better than air). And the temperature of the CO2 in the headspace will be close enough to everything else (remember -- the metal keg is a great conductor and thus will probably keep the CO2 at the exact same constant temp as the liquid).

One thing to worry about with temp stratification, though, is getting CO2 bubbles in your liquid lines, which will generate foamy pours. Putting a fan inside the kegerator to circulate air will keep it much more constant.

Question 3
I disagree with abarhan on this one. If you hit it with 20 psi and then disconnect the gas it will not be at 20 psi 10 days later. As the beer absorbs CO2 to carbonate, the pressure in the headspace drops. Because you have a small headspace, 20 psi will not carbonate an entire keg to 3 volumes. To really get technical, you'd need to know the approximate volume of your headspace to know how much pressure you'll need to hit the right carb level if you want to disconnect the gas before it's fully carbed.

Question 4
I don't disagree on this one, keep it simple, but a better explaination would be: If you fully carb at 12 psi at 33°F, then warm it at all, it will be undercarbed. As the keg warms, the solution can't hold as much CO2 and it will bubble out and build pressure in the headspace until the solution is at equilibrium again.

Question 5
You can bet that your keg is going to be somewhere between 32° and 45°, get some fans to move the air around.

What are you hoping to accomplish? Are you just curious or are you trying to do something?

PA49erFan21 said:

What are you hoping to accomplish? Are you just curious or are you trying to do something?

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Just curious really. I recently added a fan to my keggerator and am currently carbing up 20g of beer from two different batches. One batch is on day 6 and the other is on day 3. I usually take "samples" daily, especially when I've run completely dry. I like to see how the beer changes from day to day and I'm sometime shocked that the flavor can seem to be going one way (bad) and then the next day snap right back on track to delicious town.

What I have noticed is that if the fan hasn't been running recently I get what seems like a fully carbed pour, even after pouring about 4oz and dumping (into my mouth) before pouring the "official" sample. If I run the fan before pouring it's clear that the beer isn't fully carbed yet.

I have in the past had two kegs from the same batch seem completely different carb-wise from day one until they are both dry. I'm just trying to get a handle on what could cause the differences.

I can usually tell when a keg has about 4-5 beers left because A) it starts tasting like the best thing in the universe and B) it gets really foamy. So it seems like either headspace or temperature of the liquid beer in contact with the CO2 gas has a pretty big effect on how carbonated it gets. I was thinking maybe my beer would carb better now that I have the fan because the "top" beer that is in contact with the gas would be a little colder.

I sort of disagree that all the beer will be close to the same temp. My example was extreme, but liquid stratifies based on temp. In fact, at times it seems difficult to stop it from separating back into temp layers even after mixing. I think if the top of the keggerator is warm then the beer in the top of the keg is also warm.

MrFoodScientist said:

Question 3
I disagree with abarhan on this one. If you hit it with 20 psi and then disconnect the gas it will not be at 20 psi 10 days later. As the beer absorbs CO2 to carbonate, the pressure in the headspace drops. Because you have a small headspace, 20 psi will not carbonate an entire keg to 3 volumes. To really get technical, you'd need to know the approximate volume of your headspace to know how much pressure you'll need to hit the right carb level if you want to disconnect the gas before it's fully carbed.

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What I was getting at with absorption but much better said. Thanks

MrFoodScientist said:

Question 4
I don't disagree on this one, keep it simple, but a better explaination would be: If you fully carb at 12 psi at 33°F, then warm it at all, it will be undercarbed. As the keg warms, the solution can't hold as much CO2 and it will bubble out and build pressure in the headspace until the solution is at equilibrium again.

Click to expand...