Force carbing at room temp

[cgpeltier]

I'm kegging my beer for the first time and have questions about switching from force carbing at room to fridge temp.

After racking my beer and venting to remove oxygen, I set my regulator to 30psi at room temp (72) for ~36 hours. I'm hoping to get about 2.3-2.4 vol CO2.

If I disconnect the keg from CO2 and put the keg in the fridge, is there any way to estimate the dissolved CO2 after it chills (i.e., can I hook it up to the regulator and get a reading?)? If I want to finish force carbing in the fridge (now that I've cleared out fridge space), can I set it to a lower PSI and still not get overcarbonated beer?

Any advice would be great.

 

[Horseflesh]

Basically if your pre and post chill carbonation volumes are similar per the chart, you should be OK.

http://www.kegerators.com/articles/carbonation-table-pressure-chart.php

It doesn't go to 68F but your guess looks to be in the right ballpark.

So, carb it at 68F, then vent it, put it in the fridge, and put the gas on at ~5-10 PSI depending on fridge temp, length of serving line. As long as your pressure/temp in the fridge is close to the same carb result you're getting at room temp it should be OK.

However, 36 hours at 30 PSI at 68F probably won't get you fully carbonated. I carb in the fridge at 30 PSI for about that amount of time, then turn it down--the high pressure just gives me a head start.

 

[SGTSparty]

Not an expert but leaving your keg at room temp, even at 30 PSI for 36 hours is not going to carb up your beer to serving pressure. I typically leaving mine at 30 psi for about 24-36 hours at 34 degrees and I'm just about there. So that's one thing to consider.

If you're then going to move it to the fridge disconnected, I'm not sure how to estimate how many more volumes you'd pick up just based on a 30 PSI head space, probably very little if its a full keg.

If you then want to move to the fridge and continue carbing you can set it to serving pressure and not get over carbed beer as the pressure wants to be in equilibrium between the beer and the head space. BUT make sure you take your gas connection off, then purge the head space, dial down your regulator and reconnect. If you forget to do that you could get beer blown back into your regulator and ruin it.

 

[GilSwillBasementBrews]

As it gets cold it absorbs more co2 into the liquid until equilibrium is reached between pressure in the headspace and the co2 dissolved into solution. So the psi will go down as it cools. Once it is cold you can set it at normal serving pressure to let it finish off where you want it at. Here is a chart that will help you get the desired volume of co2 per temperature.
View attachment ImageUploadedByHome Brew1493138655.269735.jpg

 

[cgpeltier]

Thanks, everyone -- good information.

The keg is currently disconnected from gas and in the fridge. So, as SGTSparty said, the key now is to wait for it to chill to fridge temp, then purge headspace, dial down regulator to serving psi, then reconnect? Definitely don't want to ruin the regulator on my first attempt!

 

[Horseflesh]

I would purge it now and put it on the gas now. There is no reason not to have the gas hooked up while it chills.

 

[Dcpcooks]

You won't ruin the regulator either way. Your risk is un-carbonated beer.

 

[JONNYROTTEN]

If you set it to your serving pressure eventually it will carb to that level even warm...pretty obvious
Jumping from warm to cold carbing makes it difficult to figure out your c02 level.
Most here if not all carb at serving temp or straight from a cold crash. So the info given for time and pressure has been tested over and over and proven to work. When your all over the place with temps it makes it hard to know where your at.

Lately I've been going 40 psi for 18 to 24 hours at cold crash temps (32 deg) and has worked out well...I wont be going back to 30 psi force carb

 

[SGTSparty]

I would purge it now and put it on the gas now. There is no reason not to have the gas hooked up while it chills.

I agree with Horseflesh if you're going to have your CO2 hooked up the entire time. Based on OP's original post I thought you were going to wait a while to hook your CO2 up once you moved the keg to the fridge, possibly until you freed up enough fridge space for your CO2 tank. If you have your CO2 hooked up the entire time, then 100% disconnect, purge, dial up serving pressure and reconnect. No need to wait. That's my mistake, I misunderstood the original post.

The disconnect, purge, dial down, reconnect is just a good practice any time you're dialing down pressure because if your keg is more pressurized than your lines/regulator you can get spit beer back into your lines/regulator that can damage it.

 

[FunkedOut]

plenty of good advice already given.
here's a few more rows on that table GilSwill posted:
looks like 30psi @ 72*F will settle right at 2.4 volumes!

 

[MagicMatt]

You won't ruin the regulator either way. Your risk is un-carbonated beer.

Um, yes you can, if you don't have a check valve between the keg and the regulator and you forget to purge prior to lowering the regulator's pressure!


OP, you can also buy (or make) a keg pressure tester. I bought this one from William's Brewing and love it. I use it all the time, as I always have kegs that have been aging either at room temp or serving temp (but not hooked up to gas in a while), so it helps me monitor the carb levels and purge when needed to maintain a desired carbonation.

 

[JohnSand]

I always carb at room temp. My kegerator is full, my next batch goes on the gas at 27psi in a mid sixties basement until another batch is brewed or I need the carbed one. Then it goes in the fridge at serving pressure. I find that it needs a few days to taste right anyway, but the carbonation is good. The only time I get beer in the gas line is if I have filled the keg enough to submerge the in tube. If that is the case, don't hook up the gas until you draw some beer..

 

[SaxonSudsBrewer]

I have another interesting issue. Force carbed a Belgian farmhouse alse for the first time at ambient (68 degrees) for 4 wks at 20 psi and bottled yesterday. Seems a little undercarbed but had lots of foam. Let each bottle settle and kept filling. So I understand that I could get more carbonation by upping the psi or decreasing the temp but what about the excessive foam ?

 

[MagicMatt]

At 68°F, you should have set your regulator to around 30psi for 2.5 vols. Being a Belgian ale, you'd probably want that closer to 3.0vols, so that would mean more like 36psi @ 68°F. So yes your beer is undercarbed provided you were aiming toward the 2.5-3.0 vols range.

As for the foam, could you provide more details about how you are bottling from the keg? Using what bottler? What temp is the keg? What temp are the bottles? What pressure are you pushing the beer at?


When I bottle from the keg, the keg and bottles get chilled to 32°F to minimize foaming. Also, you should purge the headspace and then apply only 2-3psi to push the beer - just enough to get it to flow. It should take about 30 seconds to fill a bottle. When I do it this way, there is maybe 1/2 of foam (which is good, as you want a little to cap on top of and reduce O2 exposure).

 

[SaxonSudsBrewer]

Thanks MagicMatt. Very helpful. I've brewed lots but bottle conditioned and for a force carb newbie I didn't take into account the huge difference in CO2 requirement with temp differences. Bottled at same ambient 68 degree temp with a bottling wand connected to the CO2 source and keg. The beers still tastes good and is what I wanted to make, so I'm going to try to recarb it--pour it back into the keg, reconfigure the fridge and amp up the PSI. What can go wrong ........so many things but it's only beer and I'm happy to start over anyways.

 

[doug293cz]

Thanks MagicMatt. Very helpful. I've brewed lots but bottle conditioned and for a force carb newbie I didn't take into account the huge difference in CO2 requirement with temp differences. Bottled at same ambient 68 degree temp with a bottling wand connected to the CO2 source and keg. The beers still tastes good and is what I wanted to make, so I'm going to try to recarb it--pour it back into the keg, reconfigure the fridge and amp up the PSI. What can go wrong ........so many things but it's only beer and I'm happy to start over anyways.

Warm beer will foam more when dispensed than will cold beer, and a warm bottle will also encourage foam formation. As Matt said, it's best to bottle with the beer and bottles both cold.

Brew on

 

[Bobby_M]

You cannot fill bottles with carbonated beer unless that beer is in the low 30s. Chill the keg down next time.

 

[SaxonSudsBrewer]

Thanks for the help. My solution--chill the keg, uncap and pour all the beer back into it, shake the hell out of it at 30 PSI, put it in the fridge at 40 degrees at 30 PSI for 2 days, dial it back down to 14-15 and wait a week. Talked with a local brewer (has a good brew pub) and he was clear about the shaking--seemed to really suck up the CO2. Let you know in a week.

 

[S_McAndrew]

plenty of good advice already given.
here's a few more rows on that table GilSwill posted:
looks like 30psi @ 72*F will settle right at 2.4 volumes!

View attachment 398062

So how long would you leave it for at that 30PSI? Do you back it off incrementally or hold it at that pressure. I ask because i am trying to force carb (at roughly 68*) so that once carb'd properly i could bottle cleanly. Thoughts?

 

[day_trippr]

A full corny keg takes ~2 weeks at the prescribed pressure vs temperature combination to reach equilibrium. Follow the green line...

https://www.homebrewtalk.com/forum/threads/keg-force-carbing-methods-illustrated.73328/

Cheers!