Overcarbonating!

[Drunkagain]

So I've recently found myself back into brewing after a ten year break. One of the first beer I brewed up was an Imperial Stout. I made this particular recipe back when and it was great. The only thing I did different this time around was that I decided to keg it and condition it naturally in the keg over six months or so. Not lnowing better when I added the priming sugar I added the full 1 1/4 cup of DME rather than the i12 portion Ive since learned I should have used when kegging.

What should I expect from this? I know overcarbonating in a bottle can lead to gushers, but what about in a keg - foamy beer??

Thanks.

 

[Funkenjaeger]

I would expect really foamy beer. But with a keg, you have more control - you can reduce carbonation by occasionally releasing pressure, until you let enough CO2 out of solution to reach your desired carbonation level.

An article at BYO, somewhat similar, in answer to a guy who accidentally over-carbonated his beer when force carbing:
http://byo.com/mrwizard/1306.html

 

[Drunkagain]

Just out of curiosity, why do you use half the priming sugar for a keg that you would in a bottles? Its the same volume of beer.

 

[2nd Street Brewery]

In kegs you are also adding the CO2 to force it out of the keg to the equation. With bottles, once you cap em they are on thier own.

 

[Drunkagain]

In kegs you are also adding the CO2 to force it out of the keg to the equation. With bottles, once you cap em they are on thier own.

Oh yeah!

*smacks self in head*

 

[jfliv]

How does natural carbonation differ from forced when your using a keg?

At some point you are going to hook up a CO2 tank anyway, and then it will be naturally conditioned and force carbonated....

 

[Drunkagain]

How does natural carbonation differ from forced when your using a keg?

At some point you are going to hook up a CO2 tank anyway, and then it will be naturally conditioned and force carbonated....

I'll just be hooking up the CO2 to dispense not to carbonate.

 

[jfliv]

Right. but once you hook up your CO2 to the keg it will find equilibrium based on the pressure from the CO2 system... Over a couple of days, I think it would be the same as force carbonating.... but, I'm interested to find out otherwise.

 

[nick79brew]

if you naturally carbonate to 10 psi, you only need a gentle "push" of co2 maybe around 3-4 psi, yes some will be absorbed in the beer, however there is a substantial difference in naturally carbonated beer....tighter head, smoother mouth feel. Also if you naturaly carbonate you are forceing yourself to give the beer more time to age up...which is good also!

 

[jfliv]

Hmmm... For now, I'm going to accept that CO2 produced by yeast makes different bubbles than CO2 that comes from a bottle (Since I can only assume that the bottled CO2 is impure, and the CO2 from yeast may be also).

But, once you hook the keg up to the bottle, the formula changes.

Does the keg system have a one-way valve? Or am I confusing guage pressure with absolute pressure or something.... even if it did, then the bottled CO2 would be valved off until the keg pressure dropped to 3 PSIG. And then your beer would gradually reach an equilibrium of 3 PSIG... and there would be a constant exchage of CO2 at the surface of the beer between the CO2 in the beer and the CO2 in the space above the beer.

If a pressure vessel is at 10PSIG and there are 2 outlets, 1 valved outlet at 0 PSIG and one at 3 PSIG, then depending on the nozzle effect of the valves... when you opened the 0 PSIG valve (spigot) the vessel would tend to drop in pressure to 0PSIG. when the valve was then closed the vessel would tend to increase to 3 PSIG...

The piece that I'm missing is, how does the "trapped carbonation" get effected.

I know that in my glass, the beer stays pretty consistent for a while, and this is a 10PSIG carbonated beer in an open air container... but eventually, it goes flat.

If you have 3PSIG over the beer in the keg, eventually it will lose carbonation until its at equalibrium with the 3 PSIG headspace... (of course this will happen gradually as you "use up" the 10PSIG pushing your beer into your glasses).

I did a little research on the web, and found only controversy over this subject. I found one guy who said he was going to do a double blind taste test natural vs. forced, but never found the results. I am keeping my mind open, but I tend to believe that the physics and chemistry around a CO2 bubble in beer are the same regardless of where the CO2 molecules came from.

I did find a nice article on kegging... of particular interest to me was the table showing the effect of temperature and pressure on carbonating.

http://www.leeners.com/kegginghow2.html

I'm going to do more research on this... If I find something of substance, I'll post it up. I know this issue has been debated, tested, probed, and hopefully resolved before....