I am kegging my "first" batch on saturday, and have looked into it and think I understand the volumes of carbination etc. However I am confused, wont leaving the keg at serving pressure cause it to possibly become more carbonated? (add to the volume of cabonation?) Especially if it is a stout?
Won't Serving Presure Change Carbonation Volume?
- Thread starter DamageCT
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insubordinateK
Well-Known Member
Your serving pressure will directly influence your level of carbonation. I think this is an area where too much thought goes into it. Just set your pressure and forget it. If there is too much carbonation after a week, then lower it and vice versa.
No, the beer will eventually reach equilibrium with the container. That's what is meant by "fully carbonated". In fact, it will remain that way until the very last pour. It's a function of volume, pressure and temperature.
DamageCT
Well-Known Member
So you are telling me not to change the pressure for serving?
I mean in the case of a stout, if I want it at like 1.6, then I would need to run it at an even lower PSI then required to get out out of the keg...(?)
I used to change my pressure by turning off the valve. I got leaks and it was a quick and easy way to keep my CO2 tank from emptying overnight. I've since corrected my leak problem and all is good.
However, under ideal conditions (no tank leaks) you'll just keep the gas hose connected and the beer under pressure.
The carbonation will equalize to the regulator pressure and your pour should be fine if you have the correct length and diameter of hose going to the tap for the temperature of your kegerator. Close enough is close enough IMO.
Just set the regulator to the setting in the line length calculator (google it) and leave it there. Just check for gas leaks in your line...
Some people will drop the pressure in their regulator to make a less foamy pour, but I've found that doing this will cause as much foam since the beer in the line is coming out of solution due to lack of pressure causing voids and more foaming. The best solution is to get your line right and leave it at the proper PSI.
However, under ideal conditions (no tank leaks) you'll just keep the gas hose connected and the beer under pressure.
The carbonation will equalize to the regulator pressure and your pour should be fine if you have the correct length and diameter of hose going to the tap for the temperature of your kegerator. Close enough is close enough IMO.
Just set the regulator to the setting in the line length calculator (google it) and leave it there. Just check for gas leaks in your line...
Some people will drop the pressure in their regulator to make a less foamy pour, but I've found that doing this will cause as much foam since the beer in the line is coming out of solution due to lack of pressure causing voids and more foaming. The best solution is to get your line right and leave it at the proper PSI.
DamageCT
Well-Known Member
So different brews need a different length tube in order to pour correctly? Currently I have it going to a picknick tap (or whatever the "non mounted" method is called)
insubordinateK
Well-Known Member
Read my first post.
DamageCT
Well-Known Member
I have, but it confused me the most
, how can you "lower" carbonation pressure if it absorbs into the liquid? 
insubordinateK
Well-Known Member
I have, but it confused me the most
Because the amount of CO2 dissolved in the beer depends on the amount of CO2 (pressure) above the beer. It is in a state of constant flux. If the pressure is changed above the beer, the CO2 in the beer will equilibrate to the new pressure.
DamageCT
Well-Known Member
Ok, I think I understand, so I should leave my PSI at the carbonation level, and then up it when pouring and put it back down when letting it sit?
The beer will hold a certain volume of CO2 depending on the temperature and the pressure. A colder kegerator will allow more CO2 to go into solution. Also, a higher pressure will cause more CO2 to go into solution.
This is a separate thing from the serving line.
However, the serving line can determine how much CO2 will REMAIN in solution during a pour. If you carb up a beer, and then drop the pressure (to what is commonly called "serving pressure", the beer will go from a relatively stable saturation, to a suddenly lower pressure during the pour, causing it to create bubbles and foam.
Keeping the regulator pressure constant, prevents the beer from coming out or solution during a pour (until it hits the warmer glass with substantially less pressure).
The line diameter and length determines the resistance the beer encounters as it leaves the keg, and can affect the foaming of a pour.
Also, the beer will slowly lose CO2 from solution if the temperature rises, or the pressure drops. It doesn't happen right away. It works just like when it takes time to carb up a keg.
Here is a Chart that gives a temperature and pressure and line length calculation to determine the optimum of each. And remember that some beers are traditionally served at higher or lower carb levels than others. Check the style guides to know what the preferred carb level is and apply the chart accordingly.
This is a separate thing from the serving line.
However, the serving line can determine how much CO2 will REMAIN in solution during a pour. If you carb up a beer, and then drop the pressure (to what is commonly called "serving pressure", the beer will go from a relatively stable saturation, to a suddenly lower pressure during the pour, causing it to create bubbles and foam.
Keeping the regulator pressure constant, prevents the beer from coming out or solution during a pour (until it hits the warmer glass with substantially less pressure).
The line diameter and length determines the resistance the beer encounters as it leaves the keg, and can affect the foaming of a pour.
Also, the beer will slowly lose CO2 from solution if the temperature rises, or the pressure drops. It doesn't happen right away. It works just like when it takes time to carb up a keg.
Here is a Chart that gives a temperature and pressure and line length calculation to determine the optimum of each. And remember that some beers are traditionally served at higher or lower carb levels than others. Check the style guides to know what the preferred carb level is and apply the chart accordingly.
Just to be clear, optimally, you will figure out the perfect pressure for your setup on the carb chart (you should add line length or shrink line diameter if need be) on the chart and set the regulator and LEAVE IT.
insubordinateK
Well-Known Member
No - you don't have to up the pressure when pouring. Any pressure at all in the keg will enable you to pour. Just leave it at a lower setting and forget it....adjust it over time if you need to.
Make sense?
This. That's it.
DamageCT
Well-Known Member
Perfect sense, I was just looking at the calculator and saw PSI of like 6 or 7 for stouts at certain temps, while everywhere I looked said serving between 10 or 12 PSI, that is what confused me.
insubordinateK
Well-Known Member
Sounds about right for a stout. And you can serve beer at 6 PSI.
If it is not enough carbonation, bump up the pressure. If it is too much carbonation, bump down the pressure. Also figure it will take your beer a few days (a week at most) to equilibrate to the new pressure settings.
Good luck with the kegging. You will love it.
