co2 in foam but not beer?

so I've been kegging for awhile using 5 lb co2, corny, and 10' beer line (thanks for the suggestions here at hbt). I'm doing pretty well with the kegging but generally I have great foam but the beer itself is not full of crazy bubbles. In fact, I just kegged something and put it on 30 psi for about 3-4 days. Bled the keg a bit to try it, gave a nice pour with good head (on the beer), and the beer itself was flat. OK, so no co2 is getting into solution? but it's coming out in the pour like mad? Thanks ahead of time

cb

sounds like it's still undercarbed. What temp are you carbing it at?

+1 The only thing I've found that helps is time.
Even with the High Pressure/cold carb method described by BierMuncher...It takes 2 or 3 weeks before the beer is actually carbonated. Any earlier than that...I get Flat beer with a great head.

ah ha, that makes sense. I'm carbing at 38 (in the fridge) but I guess I always read force carbing should only take a day or 2. I'll check for biermunchers guide. I guess one could force carb at room temp for a quicker diffusion into solution, eh?

cb

Room temp will be slower and require a higher pressure. Chilling is recommended before hooking your gas up.

Carbing at 38 degrees with 30psi for 3-4 days should fully carbonate your beer. I usually set mine at 25psi for 48hours and have had good results.
Possible problems:
--If you completely filled the keg past the outlet of the in tube, it will take a lot longer to carb.
--Make sure that you have the gas going through the "in" tube, not the liquid out
--make sure that you don't have any leaks in your system.

Big10Seaner said:

Room temp will be slower and require a higher pressure. Chilling is recommended before hooking your gas up.

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huh?? that's backwards isn't it??

Warmer liquid will accept gas into solution a lot faster than cold beer. I force carb my kegs at room temp and about 25 lbs and they're carbed in 24 hours.

CO2 is more soluble in water at low temperatures. i can only assume beer is enough like water not to alter (reverse!) this relationship. In that case, it should be faster to carbonate at 38 degrees than at room temp!?!?!?! Pressure in the headspace (which would be the same regardless of temperature) should only serve to increase solubility.

I'm pretty sure i don't have any leaks as i'm on about keg numer 8 or 9 on one 5 gallon CO2 tank.

Gas is definitely on the 'in' tube.

Kegs have never been filled past gas in dip tube.

I'm serving at 12 PSI or thereabouts.

Warmer liquid will not accept CO2 faster. Take a look at this chart, it explains the pressure/temperature relation.

http://www.ebrew.com/primarynews/ct_carbonation_chart.htm#Carbonation_Chart

Hmmm... see that... learn something new every day. I thought it was the opposite.

that chart is a good example of what i've been basing my carbing on - and it don't work for me. if it did, why would we suggest carbing at 30 psi at first? Next time I'll try 12 psi for 5 days at 38 degrees to get 2.5 volumes.

Cape Brewing said:

Hmmm... see that... learn something new every day. I thought it was the opposite.

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I guess you've been drinking flat beer all this time.

mandoman said:

that chart is a good example of what i've been basing my carbing on - and it don't work for me. if it did, why would we suggest carbing at 30 psi at first? Next time I'll try 12 psi for 5 days at 38 degrees to get 2.5 volumes.

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5 days really isn't quite long enough. I've found it to be closer to 10-14 days.

mandoman said:

I'm pretty sure i don't have any leaks as i'm on about keg numer 8 or 9 on one 5 gallon CO2 tank.

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What about a leak in the keg? Have you tried spraying with some soapy water to check for a small leak in the keg?

quixotic said:

Possible problems:
--If you completely filled the keg past the outlet of the in tube, it will take a lot longer to carb.
--Make sure that you have the gas going through the "in" tube, not the liquid out
--make sure that you don't have any leaks in your system.

Click to expand...

This is important. Gas absorption is relative to surface area. If you have beer over your "in" tube, the surface area exposed is to gas tiny (<1/16 sq.in.). If beer is under the "in" tube, you have the whole surface of the corny (57sq.in.)

quixotic said:

--If you completely filled the keg past the outlet of the in tube, it will take a lot longer to carb.

Click to expand...

pldoolittle said:

This is important. Gas absorption is relative to surface area. If you have beer over your "in" tube, the surface area exposed is to gas tiny (<1/16 sq.in.). If beer is under the "in" tube, you have the whole surface of the corny (57sq.in.)

Click to expand...

I don't believe this is correct. The pressure inside the keg should be relatively uniform, regardless of whether the gas tube is submerged or not. Water/beer doesn't have enough surface tension to allow CO2 pressure to build up in a submerged gas tube. It all just bubbles out into the headspace of the keg. So it shouldn't matter if the gas tube is submerged or not -- the headspace pressure is basically identical.

However, if you are force carbonating using the keg-shaking method, then the volume of beer in the keg will drastically affect time to carbonation because the amount of headspace increases with less beer. In that case, there is physically more CO2 that will go into solution per 'shake' -- I found this out the hard way when I first started kegging and quick-carbed a 3 gal batch (foam city!).

EDIT: Also, it may be worth stating the obvious that the less beer you have in a keg, the faster it will carb up regardless of the method of force carbonation. So in a sense, I guess it is true that a beer that is filled to just below the gas tube will carb up (slightly) faster than the same keg filled just over the bottom of the tube. But submerging the tube should have nothing to do with it.

Agreeing with flyguy that the gas won't stop in the dip tube if it's slightly submerged. It will bubble out and fill the headspace. It's similar to running a carb stone on a long tube.

That doesn't seem right.
It's not about the pressure. If you completely fill the keg , there is less headspace and therefore less contact with between the beer and co2. Less contact = more time to carbonate. It's the same reasoning as why it takes longer to shake-force carbonate a completely full keg. Shaking a keg or using a carb stone increases the contact between the beer and co2 even more.

well I'll get to experiment, then. I have 3 batches coming on within about a week of each other and will have opportunities to try again!

I'm thinking my patience is running a bit thin and maybe I'm just not waiting long enough (expecting too much).

Also, when venting pressure to go from 30 to serving (or whatever) should you bleed all the gas off or just 'some'. My serving issue could come from not getting the pressure low enough (for fear I would be losing some pressure in the beer and potentially causing the same issue of low carbonation) although not sure that makes sense. Now I'm just guessing because I don't have a gauge that tells me how much pressures in the tank, right? Most gauges only tell us what's in the tanks not what's in the container the regulator is filling. In other words, my gauge doesn't tell me back pressure? Or am I wrong?

chris

Have you tried dispensing at a lower p.s.i.? I would lower the regulator to dispensing pressure and then bleed off the keg until you hear CO2 coming back into the keg. You won't lose carbonation because the serving pressure is high enough to keep the CO2 in solution.

Have you tried dispensing at a lower p.s.i.? I would lower the regulator to dispensing pressure and then bleed off the keg until you hear CO2 coming back into the keg. You won't lose carbonation because the serving pressure is high enough to keep the CO2 in solution.

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that sounds very reasonable - will test this on next keg(s)! Thanks.

quixotic said:

That doesn't seem right.
It's not about the pressure. If you completely fill the keg , there is less headspace and therefore less contact with between the beer and co2. Less contact = more time to carbonate. It's the same reasoning as why it takes longer to shake-force carbonate a completely full keg. Shaking a keg or using a carb stone increases the contact between the beer and co2 even more.

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It's pressure and surface area between the beer and headspace that affects the rate of absorption. If you shake, you expose just about all of the headspace full of co2 to the beer. If you leave it sit, it's the circular area on the beer's surface.

Bobby_M said:

It's pressure and surface area between the beer and headspace that affects the rate of absorption. If you shake, you expose just about all of the headspace full of co2 to the beer. If you leave it sit, it's the circular area on the beer's surface.

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I think what he was trying to say was that shaking a completely full keg with minimal headspace will take longer to carbonate than shaking a keg with with a couple inches of headspace.

Right, in that case I agree. If you have .25 gallons of co2 and 5 gallons of beer you're not exposing very much suface area when shaking as compared to say 2.75 gallons of Co2 to 2.5 gallons of beer.

Also, just to clarify, in the set and forget method where the beer's surface is the only location of absorption, the rate of carbonation is fixed. However, the more beer there is to carbonate, the longer it will take. Just for giggles, suppose that at a given pressure and surface area the rate of absorption is 1 gallon of CO2 per day. So you could get 1 gallon carbed to 2 volumes in one day or it would take 5 days for 5 gallons. That same 5 gallons would take 7.5 days for 2.5 volumes, etc.

Bobby_M said:

Right, in that case I agree. If you have .25 gallons of co2 and 5 gallons of beer you're not exposing very much suface area when shaking as compared to say 2.75 gallons of Co2 to 2.5 gallons of beer.

Also, just to clarify, in the set and forget method where the beer's surface is the only location of absorption, the rate of carbonation is fixed. However, the more beer there is to carbonate, the longer it will take. Just for giggles, suppose that at a given pressure and surface area the rate of absorption is 1 gallon of CO2 per day. So you could get 1 gallon carbed to 2 volumes in one day or it would take 5 days for 5 gallons. That same 5 gallons would take 7.5 days for 2.5 volumes, etc.

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YOU are putting WAY TOO MUCH THOUGHT into this.

Hook up gas...wait a few days...try a pint every night till it's good to go.

JoMarky said:

I think what he was trying to say was that shaking a completely full keg with minimal headspace will take longer to carbonate than shaking a keg with with a couple inches of headspace.

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Yes.
1234567890

oh, you're supposed to hook up the hoses?







:fro:

Just wanted to follow up that I figured it out. Of course, it varies a bit beer-to-beer but...

I do one of 2 things to carbonate. 1) crank up the pressure to 30, remove gas, let keg sit, repeat 1-2 times per day for 4-5 days and check carbonation level. Continue or hook up. 2) keep keg on constant 15-20 psi until carb'ed, about a week maybe. I get it now. Have to get the beer 'bubbly' in solution, then manage your actual pressure/head space for serving. I think I was (before my question) not bleeding the higher pressure from the head space and serving under hi pressure thus getting foam. Now I find I serve about 8 psi for 2-2.5 vols beers. Thanks, y'all


cb

I carb my beer in like ten to fifteen minutes. Then in twenty minutes it is going down my gullet. I cool in the keg to what ever temp im looking for. Hook the c02 up shake the keg for ten or so minutes and bada bing i have carbed beer. Screw that waiting multiple day stuff.

i hear ya, I only wait cuz carbing is part of aging for me. Beers are going into the kegs from the primary at about 2 weeks. Yeah, I've consumed all of them early but I ALWAYS notice improvement about week 5.