[Mark G]

You can lager and carbonate at the same time.

[PeckerWood]

I usually keg, co2 burp, chill overnight and hook up to co2 tank at 25psi and shake both kegs for about 10 minutes.  I let it rest overnight at 25 psi and burp again the next day and set it at around 12 psi.  It's ready to go right then and there but usually takes about a week to have the ideal carbonation and mouthfeel.

[euge]

Sure carbonation changes the beer (makes it better!), but doesn't affect how it is conditioned.

I'm fond of priming the kegs with cane sugar and let sit at room temp for a week or two and then usually sticking them in the serving fridge to crash and serve.

Often though I'll just crash the keg and hit it once or twice a day to 45psi until I like the carbonation. As Corky suggests, leaving more headspace in the keg allows it to carb faster.

[davidgzach]

Here is a handy calculator.  http://www.tastybrew.com/calculators/carbonation.html 

There are also several charts online.  http://www.kegerators.com/carbonation-table.php

It should take ~3 days to get to the recommended psi at the given temperature.  In a bind, I will crank up the pressure and shake, but if I have the time I adjust to the appropriate psi and temp and let it alone.

Dave

[hopfenundmalz]

In a pinch I have put 2 gallons of cold beer into a 3 gallon corny that was CO2 purged. Put 30 PSI on it. Unhook and then shake it with vigour. Repeated 2 more times. Waited just a little, put 10 PSI on it, and it poured with appropriate carbonation. Bottled for a competition, no comments on the carbonation that I can remember.

[redbeerman]

I guess what i was wondering is do you lager at serving pressure, or should you condition (sometimes months depending on style) at ambient (ie. airlock)? Or are lagering and conditioning two different animals?

I age my lagers on the primary yeast, then keg and carb.  Ales I primary for two weeks, generally, then keg, chill and force carb at 30-50 psi for a couple of days.  They are usually read to serve at that point, depending on the style.  Always best to over carb a touch rather thatn under carb, especially if you are going to bottle some for comps or presents.

[mabrungard]

Here is a handy calculator.  http://www.tastybrew.com/calculators/carbonation.html 

There are also several charts online.  http://www.kegerators.com/carbonation-table.php

It should take ~3 days to get to the recommended psi at the given temperature.  In a bind, I will crank up the pressure and shake, but if I have the time I adjust to the appropriate psi and temp and let it alone.

Dave

Every user of those charts should be aware that those calculations are for getting the CO2 into the beer.  There is yet another time and temperature dependent conversion of that dissolved CO2 into its aqueous form (carbonic acid).  That is why the initial carbonation is coarse and with enough time the bubbles and carbonation become finer.

[Kaiser]

I don't think that this is true since the eventual ratio between dissolved CO2 and carbonic acid is very high. Carbonic acid also breaks down very quickly which means it will be available as CO2 and can escape.

Kai

[mabrungard]

It is true.  Do a search for CO2 hydration.

While the proportion of carbonic acid is low, it is a time and temperature dependent reaction and we know that the quality of carbonation improves with time, even though we can get a bunch of carbon dioxide into solution in a very short time.  I contend that it is the CO2 hydration that affects carbonation quality, not quantity.

[davidgzach]

It is true.  Do a search for CO2 hydration.

While the proportion of carbonic acid is low, it is a time and temperature dependent reaction and we know that the quality of carbonation improves with time, even though we can get a bunch of carbon dioxide into solution in a very short time.  I contend that it is the CO2 hydration that affects carbonation quality, not quantity.

Martin,

If this is true, then I would think the "pump up the pressure and shake" method would be even less desireable, no?

Dave

[Kaiser]

It is true.  Do a search for CO2 hydration.

While the proportion of carbonic acid is low, it is a time and temperature dependent reaction and we know that the quality of carbonation improves with time, even though we can get a bunch of carbon dioxide into solution in a very short time.  I contend that it is the CO2 hydration that affects carbonation quality, not quantity.

yes I did check on carbonic acid formation and because of that I think it can't be used to explain the smoother carbonation.

at 25 C, 99.8 % of the CO2 is not converted to carbonic acid since equiblibrium will be reached before that. To me that's too little carbonic acid to make a difference. In addition to that, shouldn't soda, that sits on the shelf for a long time, also get a more softer carbonation?

Martin, I think what we have here is that the slow conversion of CO2 to carbonic acid seems a good fit to explain why beer carbonation becomes smoother with age. But that theory doesn't hold if the other aspects are considered as well.

I'm not saying that it can't play a role. I'm just contesting the mechanism and theory that have been proposed so far.

Kai

[mabrungard]

Ah, but the interaction of the complex sugars, proteins, and carbohydrates in beer with the carbonic acid is quite different from the simple sugars and lack of proteins in a soft drink.

Something is going on...the mechanism is just not well explained or researched.  Given that the only tangible change when a beer is carbonated is that additional CO2 is dissolved, the mechanism has to do with that addition.  Given the time dependency of the refinement in carbonation smoothness and the corresponding time dependency of CO2 hydration, there does seem to be a strong correlation.

[kramerog]

I pulled out my analytical chemistry textbook.  It says that only about 0.2% of dissolved CO2 is in the form of H2CO3 and that the hydration and dehydration of H2CO3 are "surprisingly slow reactions."  I think that the slow dehydration of carbonic acid provides the kinetic explanation for fine bubbles.

My textbook also indicates that there is another species of carbonate which appears to be a product of HCO3- and H2CO3 with an equilibrium constant of K=~10e3.  Perhaps this undetermined species of carbonate with perhaps other complexed forms of carbonates provides enough storage of carbonic acid for fine bubbles.

[Kaiser]

To explain the slow release of CO2 through the formation of carbonic acid we need to find a way to change the carbonic acid to something else such that the CO2/H2CO3 equilibrium is satisfied and that a significant amount of CO2 becomes something else. That means H2CO3 needs to become something else.

kamerog mentions bicarbonate (HCO3-). the relation between H2CO3 and HCO3- is determined by pH of the solution and at beer pH (~4.3) the vast majority of the carbo species will be H2CO3. So we are stuck here.

I should also note that we are working of anecdotal evidence here. Does  anyone have a pointer to a controlled experiment that examines the effect of time on quality of carbonation?

Kai

[Kaiser]

one more thing.

If a substantial amount of CO2 becomes H2CO3, then the head pressure of a closed vessel should fall over time since it is in equilibrium with the CO2 concentration and not the CO2+H2CO3 concentration. That has not been my observation.

Kai