primeing a 2.5 gal keg ?

[jimbo419]

I will be kegging half of my newest I.P.A. for the first time, not sure how much corn sugar to use as I have been told to use less than half of what would be used for bottling ? the keg is 2.5 gal. and uses the mini co.2 pressure system so it will need to be primed as I have been told and read ? first time keg jitters ! any help or input would be greatly appreciated !
thanks jimbo.

 

[wolfie7873]

What is "the mini CO2 pressure system?"

 

[jimbo419]

it's the little co.2 cylinders that you would use in an air pistol, it has a small pistol grip handle that hooks up to the mini keg that will pressurize the keg but wont force carbonate the beer, it[2.5 gal. keg ] fits on a shelf in the fridge just right. just not sure how much corn sugar to use to carbonate ? supposed to add beer and sugar cap keg and pump enough co.2 in to seal keg then condition like bottles, 2 weeks put in fridge and condition, how long ? not sure

 

[wolfie7873]

You want the long answer or the short answer?

The priming calculator here at this site works pretty well, just know that you'll need to know the temperature of the beer at kegging, the volume of the beer and the volumes of CO2 you're trying to produce.

Let's say your wanted 2.4 volumes of CO2 in 10L of beer that's at 72 degrees.

Beer that finished fermenting at 72 degrees will have about 0.81 volumes of CO2 already dissolved in it. So you need to provide the remaining (2.4-0.81=) 1.59 Volumes of CO2.

1.59 Volumes of CO2 * 10L Beer = 15.9 Liters of CO2 at STP

15.9 Liters of CO2 is 0.7098 mol CO2.

Each mole of CO2 comes from half as many moles of Dextrose, so we need 0.3549 mol of Dextrose.

Each mole of Dextrose has a mass of 180.1559 grams, so you need (0.3549 mol * 180.1559 g/mol=) 63.94 (just say 64) grams of Dextrose.

 

[jimbo419]

thanks for the help ! does any one have any idea as far as priming in a keg ? don't want to screw up the keg/over pressure ?

 

[wolfie7873]

The vessel doesn't matter. The chemistry is the same regardless. You'll have some more sediment in the bottom of the keg than if you force carbed, (just picture bottle sediment x 10L), but that should blow off in the first pint or so.

 

[GernBlanston]

thanks for the help ! does any one have any idea as far as priming in a keg ? don't want to screw up the keg/over pressure ?

Is the CO2 cylinder regulated? Does it stay attached to the keg for the duration until it is empty?
If so, then prime to achieve a carbonation level less than what you want in the final beer. Seal the keg and leave warm to carbonate (2 to 3 weeks). Then get it cold and attach the CO2 cylinder. If there is Co2 pressure in the head space, the beer will take up the remaining CO2 over time( week or two).

If the cylinder is not regulated, and only used to push the beer out, and then detached when not needed to push beer, then there would be too much pressure for the above procedure. In this case try to hit the correct pressure with the prime, and be content with what you get.

Show us a picture of this equipment if you can.