Kegging experiment

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x3la

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I have 2 Torpedo 2.5 Gallon Cocktail Kegs. These come with a removable lid like a Corny but have a Sankey D fitting.

I've brewed 5 Gallons of English Bitter and I'm going to split it between the two Kegs.

One Keg I will put in the fridge with the CO2 cylinder, the other Keg I will prime with sugar and let carbonate naturally for a month as I would do for bottle conditioning.

A few questions:

For the force carbonated keg:
  • None of the force carbonation charts seem to account for volume. Would 2.5 gallons carbonate faster than 5? is there one somewhere that accounts for this?
  • I believe I should put the keg in the fridge for a few days before starting to force carbonate. Should I set my target pressure on the regulator at room temperature before placing everything in the fridge? or after? does it matter?

For the naturally conditioned keg:
  • Should I clear the headspace by either venting with CO2 immediately after closing the keg? Some recommend doing this to seat the lid.
  • Should I just let the yeast do its thing for a few days and then lightly vent?
  • Should I leave some O2 in the headspace for the yeast?
Thanks in advance for any help.
 

AlexKay

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I have 2 Torpedo 2.5 Gallon Cocktail Kegs. These come with a removable lid like a Corny but have a Sankey D fitting.

I've brewed 5 Gallons of English Bitter and I'm going to split it between the two Kegs.

One Keg I will put in the fridge with the CO2 cylinder, the other Keg I will prime with sugar and let carbonate naturally for a month as I would do for bottle conditioning.

A few questions:

For the force carbonated keg:
  • None of the force carbonation charts seem to account for volume. Would 2.5 gallons carbonate faster than 5? is there one somewhere that accounts for this?
  • I believe I should put the keg in the fridge for a few days before starting to force carbonate. Should I set my target pressure on the regulator at room temperature before placing everything in the fridge? or after? does it matter?

For the naturally conditioned keg:
  • Should I clear the headspace by either venting with CO2 immediately after closing the keg? Some recommend doing this to seat the lid.
  • Should I just let the yeast do its thing for a few days and then lightly vent?
  • Should I leave some O2 in the headspace for the yeast?
Thanks in advance for any help.
Only pressure and temperature matter for carbonation level. I suppose there’s an argument that the smaller keg will go faster, given the larger surface area to volume ratio, but I’d expect the effect to be small. The same endpoint will be reached regardless.

No need to cool down first before force carbonation. And I -think- the pressure setting on the regulator will maintain that pressure while cooling the tank, so it doesn’t matter when you set it.

For natural carbonation, it can’t hurt to vent with CO2, especially if it helps get a good seal (this may matter more for older kegs.). You should not lightly vent after carbonation — what would the point of that be? And the yeast certainly don’t need O2; they’re fermenting, but not reproducing.
 

Broken Crow

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By simple absorbtion rates; Yes, 2.5 will be reached before 5.
For a small keg like that, I can't see it taking well beyond 4-8 hours to achieve equal temperature to the fridge, but since the internal pressure will drop while it chills, just set your regulator at your desired final setting unless you plan on doing the agitate and drop pressure later thing.
For natural in-keg-carbing, opinions may differ on this RE: O2 exposure, but my own opinion (which has not been thoroughly vetted by others!), is that it's a compromise in which my choice has been to connect my gas to the liquid out post and bubbled it into the contents causing them to foam until I see foam spurting out the PRV valve I hold open for this process under the (possibly mistaken) assumption that the bubbles I create with CO2 will help displace the O2 upwards to the PRV.
...This is just of course 'opinion' and not put to the scientific test as others on here have done, but for my ales and bitters, it has served me to my satisfaction.
:)
 
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x3la

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You should not lightly vent after carbonation — what would the point of that be?
I meant rather than use CO2 from the tank, clear the headspace of O2 by using the CO2 generated by the yeast maybe a day after priming with sugar, just enough to push out the O2. The experiment is to try and avoid using the tank altogether. I guess I risk breaking the seal on the lid doing this..
 

Broken Crow

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Sorry! I may have had an "Ooops! I did it again" moment...brain damage and I missread (thought you were referring to vol's.and probably still got it backwards)...
Volume makes no difference if temps and headspace/content ratios are equal.
clear the headspace of O2 by using the CO2 generated by the yeast
That takes time and lengthens O2 exposure, hence my personal choice to try and use CO2 bubbles to push out what O2 I could. You probably 'could' do it, but you'll have lost the natural carbonation you calculated and have to put it on gas to make it up anyway.
 

JohnDBrewer

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Yes vent both kegs with co2 after filling just the head space. I only use the gas posts as I do not want beer to come back through the gas line by hooking it to the liquid post. Try to reduce/eliminate any o2which my have gotten in. Then pressurize the kegs to 30lbs to make sure the kegs seal. For the naturally carbonated one I'll vent the keg back down 10 lbs to start off and disconnect for the co2.
 
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belgabrewing

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Been kegging for years in corny kegs. This is not hard...

Chill the filled keg. Co2 is more easily dissolved in cold fluids. Co2 is also heavier than air so connect your gas to the keg and open the corny lid. Let the gas flow for 15-30 seconds and it will displace the room air from the keg. Close the lid and let it pressurize. Be patient for a few days. If you are in a bit of a hurry, disconnect the gas and give the keg a good shake every few hours and reconnect the gas.
 

micraftbeer

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If I were doing this comparison experiment, I'd go the direction you mentioned and try not to use any bottled co2 on the natural carbonation keg. Think of it like just a bottle of beer with priming sugar- you don't crack those open and replace the cap after a day, right?
 
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